
Glass 
Book 



COPYRIGHT DEPOSIT 



A MANUAL 



OF 



HYGIENE AND SANITATION. 



BY 

SENECA EGBERT, A.M., M.D., 

PROFESSOR OF HYGIENE AND 1 DEAN OF THE MEDICO-CHIRURGICAL COLLEGE 

OF PHILADELPHIA ; MEMBER OF THE ACADEMY OF NATURAL 

SCIENCES OF PHILADELPHIA ; MEMBER OF THE 

AMERICAN MEDICAL ASSOCIATION, 

ETC. ETC. 



SECOND EDITION, ENLARGED AND THOROUGHLY REVISED. 



ILLUSTRATED WITH 77 ENGRAVINGS. 




LEA BROTHERS & CO., 

PHILADELPHIA AND NEW YOEK. 

1900. 



73152 



*i->fi<r*^ y of Ooqct 

! NOV 9 1900 

C«*yrigli< entry 

JX.M1JUL 

StCOND COPY. 
OftDW DIVISION, 

UEC 23 1900 






e 






Entered according to the Act of Congress, in the year 1900, by 

LEA BROTHERS & CO., 
In the office of the Librarian of Congress. All rights reserved. 



DORNAN, PRINTER. 



TO THE 



MEMOKY OF MY FATHEK, 



O WHOM I OWE SO MUCH ; TO WHOM I CAN BEPAY SO LITTLE, 



THIS VOLUME 



IS MOST AFFECTIONATELY 



DEDICATED. 



PREFACE TO SECOND EDITION. 



The rapid disposal of the first edition of his text-book 
has been extremely gratifying to the author, inasmuch as 
it has confirmed him in his opinion that such a work had 
'a place in the educational literature of to-day. The words 
of commendation it has received from many sources of 
authority are appreciated by him, and still more the 
helpful criticism with which he has been favored. 

The brief interval since its original issue has disclosed 
places and opportunities for improvement in its pages, 
and has in addition brought forth some new information 
which should be included in a manual of this kind. 
Especially has it seemed wise to add the Chapter on Mili- 
tary Hygiene at this time, as recent events have shown 
the necessity for practical information of that character. 

Each page has been carefully revised, and much has 
been entirely rewritten in the endeavor to make the mean- 
ing and teaching clearer and more forcible. The new 
matter on various subjects and the additional illustrations 
increase the volume to the extent of sixty-five pages. 
More foot-notes and references are likewise introduced 
with the desire to aid the reader desirous of pursuing 
special subjects. 

Trusting that this issue will be as cordially received as 
the preceding one, and again thanking his readers and 
friends, the author submits his work to their criticism and 
kindly consideration. 

Seneca Egbert. 

Philadelphia, November, 1900. 



PREFACE TO FIRST EDITION. 



For a number of years past it has seemed to the author 
that there was ueed for a manual or text-book which would 
give a plain statement of the fundamental principles and 
facts of Hygiene and Sanitation, together with such ex- 
planations and details, based on American practice, as 
would serve to make the work clear and readable. 

Of all the medical sciences, that is clearly the most im- 
portant which prevents disease instead of curing it, and 
deals with communities as well as with individuals. The 
vital interest and comparative simplicity of this science 
have already attracted the laity in great numbers, as well 
as the medical profession, and to this intelligent interest 
are largely due the remarkable advances which recent 
years have witnessed in methods of preserving the public 
health. 

The desultory and often unauthoritative articles in the 
daily press or monthly magazines are scarcely fit material 
for satisfying this desire for knowledge, nor, on the other 
hand, can we expect any extensive study of the larger 
volumes on the subject. Smaller works exist, but they 
are either diffuse and lacking in system, or they detail 
methods and devices adopted abroad and out of harmony 
with conditions here. It is important for the medical 
student, at least, that the information given in such a 
text-book as the present should be as concise and system- 
atic as possible, and that it should devote special attention 
to those conditions with which he is practically concerned. 



viii PREFACE TO FIRST EDITION. 

For these reasons, and because I have as yet found 
nothing which exactly comprises my idea, I have ventured 
to offer this volume not only to my classes, but to all who 
are desirous of doing what they can to better the health 
of themselves and of those about them. The volume 
deals with personal as well as public health. 

In the preparation of the work the principal text-books 
have been fully consulted, as well as such recent magazine 
and other articles of authority as were pertinent. Quota- 
tions have been credited and references indicated, in order 
that the reader may know where to seek for further details 
or fuller information than the limitations of this work 
will permit. Indeed, I should do wrong were I to give 
any one the idea that this volume is thoroughly compre- 
hensive, or even a compendium of the whole scope of 
hygiene or intended to be so. The science is already too 
great and too important to be treated entirely in a single 
volume, and, as it is so intimately concerned with every 
one's personal welfare, it is the author's earnest hope and 
desire that not only his students but others may use this as 
an adjunct to further and more extensive reading, and 
that, inasmuch as hygiene is destined to be even more 
important in the future than it is now, all should make 
use of all possible sources of authoritative information. 

Whatsoever may be the faults or shortcomings of the 
work, the labor expended upon it will not have been 
altogether in vain if it induces any one to take greater 
interest in the study of all that which pertains to " the 
preservation and promotion of health and the prevention 
of disease." 

The illustrations have been selected with special refer- 
ence to the text, and those of special devices or apparatus 
have been chosen as trustworthy representatives of their 



PREFACE TO FIRST EDITION. j x 

respective classes. For the four photo-micrographs of 
bacteria I am indebted to the skill and courtesy of Dr. 
William Gray, of Washington, D. C, to whom, and to 
all my other friends and associates who have aided me in 
the preparation of the work, I have many thanks to extend. 

Seneca Egbert. 

Philadelphia, May, 1898. 



CONTENTS. 



PAGE 

CHAPTER I. 
Introduction 17 



CHAPTER II. 
Bacteriology 33 

CHAPTER III. 
The Atmosphere— Air 61 

CHAPTER IV. 
Ventilation and Heating 92 

CHAPTER V. 
Water 132 

CHAPTER VI. 
Food 198 

CHAPTER VII. 
Stimulants and Beverages 242 

CHAPTER VIII. 
Peesonal Hygiene 251 

CHAPTER IX. 
School Hygiene 281 



xii CONTENTS. 

PAGE 

CHAPTER X. 
Disinfection and Quarantine 298 

CHAPTER XI. 
The Removal and Disposal oe Sewage . . . 337 

CHAPTER XII. 
Military Hygiene 369 

CHAPTER XIII. 
Vital Statistics . 388 

CHAPTER XIV. 

The Examination of Air, Water and Food . . 400 



A MANUAL OF HYGIENE AND SANITATION. 



CHAPTER I. 

INTRODUCTION. 

Hygiene may be defined as the art and science that 
considers the preservation, promotion, and improvement 
of health and the prevention of disease. It treats of the 
laws of health in the broadest sense, and under the gen- 
eral term may be included a number of subdivisions. 
Thus, while Personal and Domestic Hygiene are respec- 
tively more closely related to the affairs of the individual 
and the household, Sanitary Science also finds larger fields 
and broader application in the domain of State Medicine 
and the Hygiene of Municipalities. 

A little thought will show that under the general h< ad 
we may consider : 1. The preservation and promotion of 
health. 2. Practical disinfection and the means of avoid- 
ing preventable diseases. 3. Adaptation of diet to the 
prevention and cure of perversions of nutrition. Under 
one or another of these themes will fall the discussion of 
the air we breathe, the water we drink, the food we eat, 
the soils and surroundings of our dwellings and commun- 
ities; and at the same time the study of the means of 
recognizing, avoiding, correcting, or removing all impuri- 
ties affecting any of these. In addition, there must be 

2 



18 A MANUAL OF HYGIENE AND SANITATION. 

the study of climate and meteorology; of clothing and 
shelter; of the care of the sick, not only for their own 
sake, but that they may not endanger the well ; the 
dangers of the abuse of stimulants, narcotics, etc ; the 
desirability of chaste and temperate living, exercise, 
rest, etc. 

Parkes says that, " taking the word ' hygiene' in its 
largest sense, it signifies rules for the perfect culture of 
mind and body. It is impossible to dissociate the two. 
The body is affected by every mental or moral action; 
the mind is profoundly influenced by bodily conditions. 
[So is the moral couduct of individuals or communities.] 
For a perfect system of hygiene we must train the body, 
the intellect, and the moral faculties in a perfect and bal- 
anced order." Again, he says: "Looking only to the 
part of hygiene which concerns the physician, a perfect 
system of rules of health would be best arranged in an 
orderly series of this kind. The rules would commence 
with the regulation of the mother's health while bearing 
her child, so that the growth of the new being would be 
as perfect as possible. Then, after birth, the rules (dif- 
ferent for each sex at certain times) would embrace three 
epochs: of growth (including infancy and youth); of 
maturity, when for many years the body remains appar- 
ently stationary; of decay, when, without actual disease, 
though doubtless in consequence of some chemical changes, 
molecular feebleness commences in some part or other, 
forerunning general decay and death. In these several 
epochs of his life the human being would have to be con- 
sidered : Ftrsf, in relation to the natural conditions which 
surround him, and which are essential for life, such as the 
air he breathes, the water he drinks, etc.; in fact, in rela- 
tion to nature at large. Second, in his social and corporate 



INTRODUCTION. 19 

relations, as a member of a community with certain cus- 
toms, trades, etc.; subjected to social and political influ- 
ences, sexual relations, etc. Third, in his capacity as an 
independent being, having within himself sources of 
action, in thoughts, feelings, desires, personal habits, all 
of which affect health, and which require self- regulation 
and control. Even now, incomplete as hygiene is, such 
a work would, if followed, almost change the face of the 
world.* ' 

The student will readily see that the scope of the 
science is so vast that, in a limited work like the present 
one, it would be impossible to go over the entire ground 
completely and thoroughly. The most that may be 
attempted will be to discuss its fundamental laws as we 
now understand them, especially those that are most 
closely connected with the conscientious physician's duties 
and practice, and to show the reasons for and the advan- 
tages resulting from the pursuit of hygienic measures and 
sanitary methods based on those laws and our experi- 
ence. Hygiene is, however, a science in the study of 
which common- sense must be freely used, and if the 
student will only bring this to his aid and add to it 
sincere attention, he will speedily find that there is little 
that is difficult, beyond his grasp, or less than really fas- 
cinating. 

It has always been, as it always will be, an art to pre- 
serve health and to ward off disease. Hippocrates was 
among the first to define principles of public health or 
sanitation. He summed up the knowledge of his day 
concerning hygiene under six headings, viz.: Air, Ali- 
ment, Exercise and Rest, Sleep and Wakefulness, Reple- 
tion and Evacuation, and the Passions and Affections of 
the Mind; and he even pointed out that there must be 



20 A MANUAL OF HYGIENE AND SANITATION. 

an exact balance between food and exercise, and that 
" disease would result from excess in either direction." 1 

The excellence of the Mosaic code of the Hebrews is 
acknowledged by all sanitary authorities, and its effects 
are seen to this day in the comparative longevity of the 
race. The Greeks cultivated to the extreme both the 
physical and mental faculties, and had for their motto 
A sound mind in a sound body. The Romans, in their 
aqueducts for conveying water to the city and in the 
Cloaca Maxima, have left some wonderful examples of 
sanitary engineering, which are, in certain respects, not 
yet surpassed. All of which serves to show that the 
ancients appreciated the importance of maintaining and 
improving health, and the influence of material condi- 
tions and environment upon sanitation. 

The development of hygiene as a science, however, has 
been within comparatively recent years. Perhaps the 
first great impulse among English-speaking peoples, espe- 
cially in matters pertaining to sanitation or " State medi- 
cine/ ' can be traced to the labors of Dr. William Farr, 
and to the establishment, through his efforts, of the 
British Registrar-General' s office in 1838. 2 Since then 
the task of determining the principles and laws of health 
has been carried on with unflagging zeal by workers both 
here and abroad, and within the last score of years or 
less the knowledge gained in the new study of the bacteria, 



1 Treatise on Airs, Waters, and Places (about 400 B. C). 

2 Note should be made, however, of the writings of Johannes Petrus Frank, in 
the first quarter of the nineteenth century and even earlier, and of Parent Du 
Chatelet, between 1820 and 1836. Of the work of the former it has been said that 
"It was the first orderly presentation of that which had hitherto been known 
upon these subjects, and was the first systematic effort to rescue from chaos such 
useful information as might be of service in the organization of a department of 
sanitary supervisors, or, as the author preferred to call them, medical police." 
(A. C. Abbott, University Medical Magazine, July, 1900.) 



INTR OD UCTION. 2 1 

especially that regarding the causation and true nature of 
infectious diseases, has furnished us with a wealth of facts 
with and by which we may make the foundations of our 
science more secure and lasting. 

It would be wrong, nevertheless, to give the impres- 
sion that hygiene is, as yet, an exact science. While 
it is rapidly attracting popular notice and attention, 
and has attained within comparatively recent years a 
dignity that it did not hitherto have in this new world, 
it is already on a somewhat firmer basis in the old. 
The brightest minds of the day are still busy with many 
of its problems, and facts and laws are being made clear 
that more firmly fix or may altogether change some of our 
beliefs and our practice. Especially is such new knowl- 
edge to be sought for in the study of the prevention of 
disease, the domain of bacteriology, the parasitic diseases, 
and the chemistry of the animal alkaloids and kindred 
compounds. 

Perhaps a few statistics will help one to realize that the 
study is not in vain, and that the promise of the future is 
even more brilliant than the results and achievements of 
the past. Three centuries ago the death-rate of London 
was more than eighty per thousand; now it is about 
twenty. It is computed that in the eighteenth century 
— the one preceding the introduction of vaccination — fifty 
millions of people were killed in Europe by smallpox 
alone; now it is practically almost an extinct disease. In 
1872 Sir John Simon estimated " that the deaths which 
occur in England are fully a third more numerous than 
they would be if our existing knowledge of the chief 
causes of disease were reasonably well applied through- 
out the country, and that of deaths which in this sense 
may be called preventable the average yearly number in 



22 A MANUAL OF HYGIENE AND SANITATION 

England and Wales is about 120,000." In confirmation 
of the accuracy of this statement, official reports show 
that the annual death-rate of England and Wales, which 
averaged 22.6 per 1000 for the decade from 1862 to 1871 
inclusive, fell to 18.9 for 1881, this giving a saving of 
92,000 lives annually; while for 1 889, even with the correc- 
tion for the lowered birth-rate, it was only 17.9, indicating 
a yearly saving of at least 125,000 lives, and completely 
substantiating the above estimate of Simon. Moreover, 
the death-rate from the seven principal zymotic (infectious) 
diseases had dropped from an average of 4. 11 for the period 
from 1861 to 1870 to 2.40 for 1881-1885, and that of 
typhoid fever from 0.39 per 1000 in 1869 to 0.137 in 1892. 
This for England and Wales. In Munich from 1866 to 
1881 the average yearly hospital admissions of typhoid 
fever cases were 594, or 3.32 per 1000 of population, and 
the average deaths from this disease were 208, or 1.15 per 
1000. From 1881 to 1888, following the introduction of 
improved systems of sewerage and a better water-supply, 
the average hospital admissions (typhoid) were 104, or 
only 0.42 per 1000, and the average deaths were 40, or 
only 0.16 per 1000 of population. 

In this country a like improvement is to be noted, 
though it is only within the last few decades that much 
attention has been given to sanitary affairs. The death- 
rate of most of our cities is being progressively lowered, 
though the populations are constantly increased by large 
numbers of ignorant and uncleanly immigrants from 
abroad. Improved sanitary laws are being enacted and 
enforced, streets better paved and cared for, houses more 
properly constructed and ventilated, more attention given 
to isolating the sick and protecting the well, and the 
people in general are awakening to the importance of im- 



INTB OD UCTION. 23 

proving as well as maintaining the public health. New 
Yurk has reduced her death-rate per thousand within the 
last decade (1889 to 1899) from 25.32 to 18.41; Phila- 
delphia, from 19,74 to 18.78; Boston, from 23.52 to 
20.12, etc. 1 

Nevertheless, there is still much to be done. Tuber- 
culosis, which is said to cause from one-seventh to one- 
fourth of all the deaths in the civilized world, is practically 
a preventable disease, and we now not only know its cause 
but also have efficient means for a cure in a large propor- 
tion of cases, as well as for its general prevention. So with 
a number of the other infectious diseases. Almost every 
day marks an increase in our knowledge of their etiology 
and the securing of immunity from them, and not only 
must physicians make use of this knowledge as they ac- 
quire it, and employ their utmost endeavors to secure the 
enactment and enforcement of sanitary laws and regula- 
tions, but they must realize that a large part of their work 
lies in the enlightenment and education of the people in 
all matters pertaining to the public health. 2 

In the preparation for a study like the one on which we 
are about to enter there is some question as to just what 
may be the most advantageous order and arrangement of 
the subjects to be treated. For instance, it would be 



1 The importance of such statistics is not fully appreciated unless the reader 
remembers that in a city of, say, a million inhabitants a reduction of the death- 
rate one point means the saving of one thousand lives annually. 

2 It is encouraging to find that, although almost 12 per cent, of the whole num- 
ber of deaths recorded in Philadelphia in 1899 were caused by consumption, a 
progressive and marked lowering of the death-rate from this disease in that city 
is taking place, and that, notwithstanding an increase in population of over 33.4 
per cent., the fatalities from this disease are actually less in number than they 
were fourteen or fifteen years ago. For example, the deaths from pulmonary 
tuberculosis in 1885 numbered 2821, and in 1886 were 2»34, rates respectively of 
2.97 and 2.92 per 1000 living ; while in 1899 there were only 2818 deaths, or a rate 
of 2.23 to 1000 living. 



24 A MANUAL OF HYGIENE AND SANITATION. 

interesting to discuss our scieuce in its relation, in turn, to 
the individual, the household, and the people in general 
— that is, personal, domestic, and public hygiene; and to 
show wherein the treatment of these subdivisions is sim- 
ilar and wherein they differ. Such a threefold considera- 
tion would be not only logical, but extremely instructive. 

However, since the bacteria have been shown to have 
so important a part in many of the processes intimately 
connected with health or disease, it will doubtless be 
advisable to devote the next chapter to a brief review of 
the science of bacteriology. This done, it seems to the 
writer that we shall, as beginners, obtain a more compre- 
hensive and thorough view of our subject if we pursue a 
method somewhat as follows : First, to discuss air, water, 
aud food — three things absolutely essential to life — in the 
varying conditions and circumstances under which they 
may affect the physical welfare, either for good or bad, 
of the individual or of the community. Then to take up, 
in such order as may seem best, the other themes, whose 
consideration is only a degree less important than the 
above on account of their influence in the preservation 
of health aud prevention of disease, such as clima- 
tology, habitations, disinfection and quarantine, disposal 
of sewage, clothing, exercise, school hygiene, etc. In 
this way, while the whole ground may not be covered, 
the importance of the various subdivisions may be esti- 
mated in their relationship to one another, and we shall 
be the better prepared to pursue the study as opportunity 
may offer in the future. 

It is doubtless in place just here to review briefly the 
reasons why it is the special duty of the physician to be 
able to recognize and remove insanitary conditions where- 
ever they may be found, aud why he should make par- 



INTRODUCTION. 25 

ticular and constant study of the science in all its branches 
and developments. 

Every true physician soon finds that the respect and 
affection of his patients and associates are worth far more 
than mere mercenary gain, and that his highest aim should 
be to prevent disease rather than simply to cure it; and, 
though this may seem to militate against his personal in- 
terests, he is unworthy the name of physician if his object 
and purpose is solely or primarily to make money. How- 
ever, the observer quickly learns that in a community 
kept in good health and hygienic condition there will 
always be more or less need of a doctor's services, in 
spite of every effort to prevent sickness, and that such a 
community will pay more promptly and more liberally 
for such services than one in which all sanitary precau- 
tions are neglected. Health means ability to work and 
to earn good wages; and a healthy community means more 
business, more money, and more comforts. Moreover, as 
a rule, good wages ensure prompt and cheerful payment 
of the doctor's bills, as well as of others. We may note 
here the close relations existing between sanitary science 
and social and political economy — a relationship which is 
very intimate, as we shall see from time to time in our 
work, for as the physical condition of a people is bettered 
it becomes more possible and more certain that they will 
likewise improve both mentally and morally. 

Again, though the science of hygiene and sanitation is 
comparatively a new one, public attention is being strongly 
directed toward it, not only because it vitally interests 
every one, but because new discoveries and new appli- 
cations of the laws pertaining to it are being constantly 
made, which are, in turn, swiftly given to the world by 
both the scientific and the popular press. This creates a 



26 A MANUAL OF HYGIENE AND SANITATION. 

demand for first class teachers, which demand is bound 
to increase in the near future and promises materially 
to exceed the supply. In fact, within a very few years 
not only the medical, but the academic and scientific col- 
leges of the country will be compelled by powerful public 
opinion to establish in their faculties well-equipped and 
well-endowed chairs of hygiene and sanitary science, and 
it will be from the ranks of the educated physicians of 
the country that these teachers must naturally come. It 
will not be long before the people in general realize that it 
is fully as important that the college student or graduate be 
instructed how to do his part in taking care of the health 
of himself, his future family, and the community in which 
he is to reside, as that he shall be well taught in the 
abstract principles of theology or the classics of dead 
languages. 

So, also, considerably more time and attention than are 
now accorded to it should be given to hygiene in the work 
of the various normal schools for teachers. The graduates 
of these schools will have much of the physical as well as 
the mental welfare of thousands of young and growing 
children in their keeping, and it is unquestionably their 
duty to prevent or obviate the ills of school life as far as 
lies in their power, and to give instruction in and to in- 
culcate habits of living which will continually tend to pre- 
serve and improve the physical health of those under their 
care. One need scarcely intimate that, as the subject and 
its study are comparatively new and the demand for in- 
structors is likely to be in excess of the supply, the recom- 
pense of the latter should be accordingly lucrative. 

Lastly, the time has come when a physician must neces- 
sarily have a knowledge of hygiene, preventive medicine, 
and sanitary science. Many States require as thorough 



- 



INTB OD UCTION. 27 

examinations in this as in any other branch of medicine 
before granting the right to practice within their bounda- 
ries. So do the army, navy, and marine hospital services 
of the Government. Moreover, the people generally, as 
has been intimated, are awakening to an interest in sani- 
tary matters and the prevention of disease, and expect 
their physicians to be well versed on all pertaining sub- 
jects; if they find a doctor lacking in knowledge or in- 
terest in this respect, they are apt to think, rightly or 
wrongly, that he will also be deficient in the other 
branches of medicine. 

Happily these causes all combine to place preventive 
on the same high plane with curative medicine, and the 
time is fast passing in which the chair of hygiene fails 
to have a primary place in any thorough medical school. 
May the day soon come when it shall have at least equal 
importance in the curriculum of all academic and normal 
colleges and schools. 

It is evident that the successful physician and practical 
student of hygiene must have a thorough knowledge of 
three things: 1. Health and its laws; how to obtain and 
preserve it. This, of course, implies a knowledge of the 
human body and its functions, viz., of anatomy, physi- 
ology, and physiological chemistry. 2. He must study 
disease and its causes and nature. He must also under- 
stand the distinction between diseases due to causes ex- 
ternal and those due to causes internal to the body; and 
that while some of these causes may be prevented or 
modified, others, with our present knowledge, may not 
be so readily overcome. 3. He must be conversant with 
and know how to use the therapeutic agents, both pre- 
ventive and curative, that he has at his disposal, including 
not only drugs, but also all substances and forces that he 



28 A MANUAL OF HYGIENE AND SANITATION. 

can make efficacious to his purpose. The workman must 
know his tools to be able to use them intelligently. 

Health is " that condition of the body and its organs 
necessary to the proper performance of their normal 
functions/' and disease may be defined as " a condition 
of the body marked by inharmonious action of one or 
more of the various tissues or organs, owing to abnormal 
condition or structural change." It is, accordingly, well 
to consider briefly the nature and causes of disease, that 
we may the better understand the influence upon its pre- 
vention or production of all those varying factors, phases, 
and conditions of our environment which we hope to study 
in our work. 

Disease is an entity, not a spiritual thing; a condition, 
not a theory. Consequently, it is to be fought and, if 
possible, conquered with matter, force, and physical means, 
though not necessarily with violence. In fact, when once 
we understand the minuteness and delicate structure of 
the ultimate cells and tissues affected, we realize that, 
oftentimes the gentlest application of the forces and means 
employed may be the most helpful and efficient. But 
when one has seen the ravages caused by it, as revealed 
in the pathological laboratory and at autopsies, not to 
speak of its manifestations in the -living, as seen in the 
sick-room and in hospitals, I am sure that he cannot 
logically, or even for a moment, give credence to those 
who proclaim that it can be dissipated by the mere action 
of mind or of faith; nor to those others who declare that 
by subdividing and diluting and subdividing again infini- 
tesimally a single grain of substance, whether primarily 
powerful or inert, you endow it with a miraculous power 
to remove the " ills that flesh is heir to." Virchow 
gave a priceless boon to modern medicine in his theory of 



INTR OB UGTION. 29 

cellular pathology and in showing its superiority to the 
old humoral theories and a priori reasoning. He wrote 
" whatever outside of a cell acts upon it (abnormally) 
works a mechanical or chemical change within it, which 
change is disorder or disease." The sooner we realize 
that the laws of physics and chemistry govern cell life 
and action and, consequently, the functions and organs of 
the body, the more accurate will be our treatment and 
the more certain our prevention of disease. 

For convenience sake, diseases may be divided into two 
main classes, somewhat different in their origin, nature, 
and character, although the line between the two is not 
always clearly marked. Diseases of the first class arise 
within the body, and are usually due to some alteration 
or disturbance of nutrition and assimilation, or of func- 
tion, and may be called autogenetic. The second class 
comprises those which are due to causes from without, 
favored, it may be, by either internal or external predis- 
posing conditions, but each of necessity depending upon 
the reception or inoculation of the special cause, which 
cause has the power of reproduction and development, 
of vitality and virulence. Such diseases are called con- 
tagious, infectious, specific, or zymotic. 

A third class or a subdivision might also be indicated, 
which would include those maladies which are almost 
purely psychical and whose symptoms are largely notional 
and the result of perverted imagination. But it is a ques- 
tion whether the primary cause of almost all such disorders 
is not an altered and abnormal nutrition or functioning of 
the general nervous economy of the body and the symp- 
toms simply the reflex manifestations of irritative dis- 
turbances of distant organs. 

In the first class, with our present knowledge, we 



. 



30 A MANUAL OF HYGIENE AND SANITATION. 

should place such maladies as rheumatism, gout, diabetes, 
neurasthenia, etc.; while into the second will obviously 
fall all that are now known to be due to living " germs " 
or organisms, such as cholera, typhoid fever, malaria, 
etc. However, we must not overlook the numerous im- 
pulses often given to the causation of certain members of 
the second class by faulty conditions of nutrition or 
assimilation, as is especially exemplified in many easel 
of tuberculosis. The character of the soil may influence 
the growth and product of a plant almost as much as the 
species itself, and so the difference in constitution and 
tissue of individuals may materially determine the varia- 
tion in symptoms and virulence so often manifested by an 
infectious malady. 

Prophylaxis is " the use of hygienic or other precau- 
tions conducive to the prevention of disease ;" or it may 
be defined as u a series of methods or procedures whereby 
disease is restricted and prevented by suppressing or re- 
moving its predisposing conditions, and destroying or 
modifying the exciting causes." Its first function, of 
suppressing or removing predisposing conditions, is 
accomplished by sanitation ; the second, that of destroy- 
ing or modifying exciting causes, is carried out by disin- 
fection. The term "predisposing conditions" should be 
used instead of " predisposing causes," because these con- 
ditions cannot in themselves originate a disease, though 
they may make the system more susceptible to the ex- 
citing causes of a disease. 

As we have, as yet, very little definite knowledge of 
the real nature of the exciting causes of autogenetic dis- 
eases, they beiug developed and elaborated within the body, 
and as disinfection, or the destruction and modification 
of exciting causes, is an essential feature of prophylaxis, 



INTB OD UCTION. 3 1 

we, at present, naturally look for more immediate and 
satisfactory results in the application of prophylaxis to 
the second class of diseases; but it does not prevent or 
restrict the employment of certain prophylactic measures 
in regard to the first class, such as the selection of proper 
diet, clothing, climate, etc., and the removal or counter- 
acting of all causes favoring malnutrition or imperfect 
functional activity. We may, therefore, say that sanita- 
tion is the defensive, disinfection the aggressive part of 
prophylaxis. 

To suppress and remove predisposing conditions and to 
prepare the body to resist and repel the action of exciting 
causes, we must not only strengthen its powers of resist- 
ance but also make all external media as favorable to it 
and as hostile to the exciting causes as possible. 

The defensive powers of the body must lie in the indi- 
vidual cells and tissues of the body, including the vital 
fluids, and it is but natural to suppose that this repellent 
action to noxious substances is best performed when the 
cells and tissues are in most perfect health and most vig- 
orous condition. This is not only good logic, but all our 
experience and scientific research go to show that it has a 
firm foundation in fact. 

We shall soon learn that purity of the external media 
and environment of the body is essential to its welfare 
and that of its component tissues, and that conditions of 
impurity in these media predispose to disease. We shall 
also learn that a proper and sufficient supply of whole- 
some food is essential to health, and that certain other 
factors, as sex, age, clothing, climate, etc., may act for 
good or ill in the determination of the relationship or bal- 
ance between health and disease. In other words, if we 
strengthen the resistant powers of the system to the fullest 



32 A MANUAL OF HYGIENE AND SANITATION. 

extent and remove all predisposing conditions, in all prob- 
ability the exciting causes will be inoperative, and there 
will be do incurrence of disease. This is the essence of 
sanitation : to secure perfect health, to increase the in- 
herent power to resist noxious and harmful influences, 
and to make all the surroundings and environments of 
the body pure and free from depressing factors. This 
applies equally to both classes of disease; for with healthy 
cells and proper food there will not be faulty nutrition 
and assimilation or improper functioning and the conse- 
quent production of the exciting causes of autogenetic 
disease; and with a vigorous resistance and pure sur- 
roundings there is little opportunity for the germs of in- 
fectious maladies to obtain a foothold within the system 
long enough to reproduce themselves and cause their 
characteristic diseases. The best means, therefore, of 
preventing disease is to learn and apply the best means 
of attaining and retaining a healthy and vigorous state of 
the system, viz., to determine and observe the laws of 
hygiene. 



CHAPTER II. 

BACTERIOLOGY. 

The increase in the knowledge concerning the lowest 
forms of life, and the discovery within recent years that 
these often have a truly causative action in the excitation 
of many maladies, have greatly facilitated the study of 
the prevention of disease. In fact, it is largely to this 
advance in knowledge and to the confirmation of the 
germ theory that much of the success of modern hygiene 
and sanitation is due. In addition, many species of bac- 
teria are of extreme importance because their function is 
that of scavengers, continually working to remove and 
convert the useless and harmful wastes of the world into 
matters of high value as food for organic life; while still 
other kinds are being found to have great value in many 
strictly commercial processes. A review of the chief facts 
concerning them will, therefore, be in place at this time. 

The unicellular, vegetal micro-organisms divide them- 
selves into two general classes with respect to their manner 
of reproduction, viz., those that multiply by budding — the 
blastomycetes — and those that increase by simple division 
or fission — the schizomycetes. In the former class we have 
the hyphomycetes or mould-fungi, and the saccharomy- 
cetes or yeasts, examples of these being famil'ar to every 
one. However, it is with the fission-fungi, or bacteria, 
as they are now more generally known, that we are most 
concerned as sanitarians, since they practically include 

3 






34 A MANUAL OF HYGIENE AND SANITATION. 

almost all those vegetal micro-organisms that are more or 
less closely connected with the production of disease and 
the removal of offensive matter. Comparatively few of 
the yeasts and moulds are pathogenic, and then only in- 
directly or in a minor degree. 

Bacteriology, then, is the science of those unicellular, 
vegetal micro-organisms that multiply by direct division 
(fission), or, as occasionally happens, by the development of 
spores. Its study consists in the examination by means of 
the microscope of the form and method of growth of these 
minute plants, in their artificial cultivation on or in suit- 
able media, and in the determination of the effects of the 
inoculation of pure cultures upon animals. To this may 
be added another field of research that gives promise of 
rapid development in the near future, viz., the study of 
the chemistry of the bacterial products and the reactions 
produced by them in culture media and in living tissues. 

Although more than two centuries have elapsed since 
the discovery of the bacteria by Leeuwenhoek (about 
1680), and though Plenciz advanced as early as 1762 
what is practically the germ theory of to-day, most of our 
knowledge concerning the physiology, methods of culti- 
vation, and differentiation of the bacteria have been 
acquired within the last fifteen or twenty years. It is 
true that some earlier advance had been made in sterili- 
zation, and that Cohn, by establishing the fact of spore- 
formation, demolished the last arguments in favor of 
spontaneous generation, and confirmed the science of bac- 
teriology; but until the few years just preceding the last 
two decades we had but little knowledge as to the means 
of separating and isolating the different species and mak- 
ing pure cultures, or of preparing culture media, staining, 
etc. 



BACTERIOLOGY. 



35 



As already intimated, the bacteria are unicellular organ- 
isms, usually multiplying by a process of cell-elongation 
and fission. Being deprived of chlorophyll, they cannot 
absorb and decompose carbonic acid and ammonia, as do 
the higher plants; but require for their growth and nutri- 
tion organic matter — usually soluble albumin — in the pres- 
ence of moisture. 1 Hence they must be either saprophytes 
or parasites. As the combination of albuminous organic 



Fig. 1. 




Micrococci (gonococcus) in pus-cells X 1000. 

matter and water is extremely common, so the distribu- 
tion of the bacteria over the earth is widespread and prac- 
tically universal. 

Some of the bacteria may, under adverse conditions, 
such as lack of nutriment or moisture, too alkaline or too 
acid a medium, extremes of temperature, etc., or, on the 

1 It will be understood that these statements and many of those to follow are 
more or less general, and that certain species of the bacteria may present notable 
exceptions. 



36 A MANUAL OF HYGIENE AND SANITATION. 

other hand, as a result of the attainment of a stage of 
maximum development, produce spores which are much 
more strongly resistant to deleterious influences than the 
bacteria themselves. In this way the spore-forming 
species may often survive the action of disinfectants or 
other agencies that are sufficient to destroy other bacteria. 
Upon the resumption or recurrence of favorable conditions 
the spores develop into cells similar in form and nature 



Fig. 2. 




<# 



«4S 








Tubercle bacilli in sputum. X 1000. 



to their parent cells. It is to be remembered that spores 
do not reproduce spores, and that " a single cell produces 
but one spore. m 

Under the microscope the spores are seen as highly 
refractive, spherical bodies that stain with difficulty, and 
evidently have a very resistant envelope, probably of cellu- 
lose. The interior of bacteria and spores is protoplasm. 

1 Abbott: " Principles of Bacteriology," 1st ed., p. 31. 



BACTERIOLOGY. 37 

So far as we positively know at this time, only certain of the 
bacilli form spores, while a few of the spirilla and one or 
two species of micrococci probably have the same faculty. 

Again, under certain peculiar conditions some organisms 
may develop another morphological change, the so-called 
involution forms. These are doubtless pathologically 
distorted cells, with probably less than normal resisting 
powers, but which will again revert to the normal under 
favorable conditions, providing the unfavorable environ- 
ment does not first kill them. 

Lastly, there are times when certain individuals of a 
species seem to have departed from the typical form, 
these departures being only different phases in the normal 
development. Thus a young bacillus may be shorter 
than the adult and look much like a coccus, or a coccus 
about to undergo division may be oval in shape and con- 
siderably larger than the quiescent members of its species. 
But one form of bacteria never permanently takes that of 
another — micrococci are always micrococci, bacilli always 
bacilli, etc. 

A thoroughly scientific classification of the bacteria is 
scarcely possible as yet, owing to our incomplete knowl- 
edge of their character, method of growth, physiology, 
etc. However, there are a number of ways in w 7 hich we 
may subdivide them, none of them exactly scientific, per- 
haps, but still sufficiently accurate and convenient for 
our purpose. If we consider them as to form we have: 
(a) micrococci, spherical in shape; (b) bacilli, which have 
one diameter longer than another; and (c) spirilla, spirals 
or segments of spirals. We shall have more to say here- 
after of the characteristics of each of these subdivisions. 
Accordingly as they live best with or without air or oxy- 
gen they are aerobic or anaerobic. Again, they may be 



38 A MANUAL OF HYGIENE AND SANITATION. 

named according to their product — e. g. y some produce 
colors, chromogenic, others pus, pyogenic, etc. Lastly, 
they exist and grow either as saprophytes upon dead or 
as parasites upon living organic matter. We also say 
that an organism is optional or facultative when it is at 
one time a saprophyte and at another a parasite, or at one 
time aerobic and again anaerobic; and that it is obligate 
when it has not this property of changing its nature 
according to surrounding conditions. 

Some of the micrococci are named according to the 
manner in which they grow. If in pairs, they are called 
diplococci; in fours, tetracocci; in threads, streptococci, 
etc. Groups or masses of micrococci or bacilli held to- 
gether by a gelatinous substance are called zooglea. With 
one or two exceptions we know but little about the spirilla. 
The germ of cholera — the comma bacillus (?) — belongs to 
this class, and the cause of relapsing fever is also prob- 
ably a spirillum. 

Most of the bacteria thrive best in culture media that 
are neutral or only slightly alkaline, though a few species 
seem to do better in slightly acid surroundings. So, also, 
they do best at temperatures ranging between 20° and 
40° C. (68° and 104° F.), though they may grow at any 
temperature between 5° and 43° C. (41° and 109.4° F.). 
Any marked deviation in the culture media from the 
neutral point or continued exposure to extremes of tem- 
perature may either check the growth of the organisms 
altogether, and eventually destroy them, or may cause 
spore-formation, or the production of involution forms, 
or a change in the composition and the character of the 
chemical products which the bacteria normally produce. 
This also holds good with respect to any other condition 
or substance that may be deleterious to the bacteria in 



BACTERIOLOGY. 39 

their normal state; wherefore we shall see that this is 
important as having a decided influence in altering the 
virulence of pathogenic bacteria and in supplying methods 
for bringing about a condition of immunity to their 
attacks. 

As it is rare to find isolated individual species any- 
where except in pure cultures artificially prepared, it is 
evident that we must devise some way of separating the 



Fig. 3. 




* *w it 



*v > 
J 



Spirillum of Asiatic cholera. X 1003. 



different kinds of organisms one from another. This is 
best accomplished by the method suggested by Koch, viz., 
to introduce the mixed kinds into some melted culture 
medium, like nutrient gelatin, which solidifies on cool- 
ing, but whose melting-point is not sufficiently high to 
destroy the vitality of the germs. If the fluid be well 
shaken, the various species will be distributed through 
it, and upon cooling each individual or group (zooglea) 



. 



40 A MANUAL OF HYGIENE AND SANITATION. 

of individuals of the same kind will be fixed in its place 
and become the starting-point of a colony of that special 
kind. Moreover, if the gelatin be poured out before 



Fig. 4. 



^■>* 



Ski . ,~-^--y~^ — •> j* 







Bacilli of hog cholera, showing flagellce. X 1000. 

cooling upon sterilized glass plates or into flat (Petri) 
dishes (Fig. 5), the subsequent work of counting, exarn- 



FlG. 5. 




Petri double dish, now generally used iustead of plates. 

ining, and making cultures from the colonies will be 
greatly facilitated, while by transplanting from the colo- 
nies thus secured the process may be repeated until abso- 



BACTERIOLOGY. 



41 



lutely pure cultures of each species in the original mixture 
are obtained. 

Special care must be taken in this, as in all other bacte- 
riological methods or operations, to prevent contamination 
of our cultures, media, or apparatus by other organisms, 
which are almost omnipresent, and which would prevent 
any accurate results or deductions whatever, were they 
not rigidly excluded or destroyed. Obviously, we may 
not use the ordinary chemical disinfectants or antiseptics 
as a means of destroying and removing these interfering 
microbes, for such procedure would destroy or check the 
growth of the bacteria we desire to cultivate; but we must 
sterilize by heat all the articles we use, together with their 
contents. This, if properly done, does not affect the 
nutrient properties of the culture media, while it does 
remove the danger of contamination already present. 

In sterilizing we may use either dry or moist heat, 
the latter being by far more preferable in most cases, 
since to be effectual it does not require so high a tem- 
perature nor so long a time as does the former. Moist 
heat, especially in the form of steam, is more penetrating 
than dry heat ; beside, the dry heat must be of so high 
a temperature that it may spoil for culture purposes 
such substances as the nutrient gelatin. Glassware and 
the like, however, may be quickly and advantageously 
sterilized by dry heat. On the other hand, certain sub- 
stances, like blood-serum, are ruined by moist heat con- 
tinued long enough to destroy the spores possibly present, 
as the latter need a higher temperature or longer heating 
to sterilize them than the bacteria without spores. So 
we resort to fractional sterilization in such cases, exposing 
our materials for only a short time to a temperature just 
sufficient to destroy the bacteria, repeating the process 



42 A MANUAL OF HYGIENE AND SANITATION. 



after an interval, say twenty -four hours, which is pre- 
sumably sufficient to allow the spores to develop into 
bacteria, and again a third time, after a like interval, to 
ensure absolute sterilization. Previous to sterilizing the 
culture media and apparatus we prevent the subsequent 
access of additional and contaminating germs to the inte- 
rior of our tubes and vessels by plugs of cotton-wool, 



Fig. 6. 





Steam sterilizer, pattern of Koch. 

covering these, when necessary, with rubber caps to pre- 
vent the evaporation of fluids, or of moisture from the 
gelatin, etc. 

As a basis for a number of culture media we may use 
beef-broth or bouillon, which is a fluid especially favor- 
able to bacterial growth, in that it contains an abundance 
of albumin in solution. When a solid medium is desired, 



BACTERIOLOGY. 



43 



either gelatin or agar-agar (a sort of vegetable gelatin 
from Japan) may be added to this, giving us nutrient 
gelatin and nutrient agar-agar. Of these, the gelatin 
has a melting-point below the temperature of the human 
body, while the agar has not; so we have to employ the 
latter when it is desired to cultivate germs that grow 
best at the body-temperature, although the development 
of most bacteria is usually more rapid and characteristic 



Fig. 7. 




Arnold steam sterilizer. 



upon the gelatin. Sterilized and solidified blood-serum 
is also used for the cultivation of certain organisms, like 
the diphtheria bacillus, and there are certain others which 
can only be identified by their difference in growth upon 
boiled potato, milk, etc. 

The differentiation of the various species of bacteria is 
to be made by noting their appearance and form under 
the microscope, whether they are motile or not, how they 



44 A MANUAL OF HYGIENE AND SANITATION. 

take different stains, etc.; by observing their methods of 
growth in or upon different culture media and the color 
and appearance of the colonies; by noting whether they 
are aerobic or anaerobic, or facultative, and at what 
temperatures they do best, etc. ; and finally by studying 
their action and the action of their products upon living 
animals. In this way we may determine the character- 
istics of each individual or species, and will eventually 
have the groundwork and material for a strictly scientific 
classification of the bacteria. For example, the organisms 
causing suppuration are usually micrococci, occurring in 
clusters (staphylococci) or in chains (streptococci); the 



Fig. 8. 




Ruled square for counting colonies. 



cause of typhoid fever is a bacillus, and the cholera germ 
belongs to the spirilla. The tubercle bacillus stains with 
marked difficulty, but when stained is not readily decol- 
orized by a weak solution of nitric acid, as are almost all 
other bacilli. Some bacteria liquefy nutrient gelatin, 
others do not, and almost none liquefy agar-agar. This 
liquefaction is not a melting, but rather a probable pep- 
tonization, since the gelatin will not solidify again after 
it occurs, as it does after beiug subjected to moderate 
warming. Again, some bacteria produce one color or 
chemical substance in the presence of oxygen, and an- 
other in its absence; some produce color only in the light, 



BACTERIOLOGY. 



45 



others only in the dark, etc. Finally, as we already 
know, different pathogenic microbes produce different 
maladies when inoculated in animals or human beings, 
and the same germ may produce different results in ani- 
mals of different species or families. 1 



Fig. 9. 




Pocket-case containing sterilized culture tubes, platinum needle, and small 
alcohol lamp, used for obtaining cultures for diagnosis, etc. 

The subdivision of the bacteria into saprophytes and 
parasites has already been noted. Therefore, it must be 
remembered that not all of these microscopic plants are 
disease-producers; much the larger proportion, in fact, 



1 See Kenwood's " Hygienic Laboratory," pp. 466-470 ; also McFarland's " Path- 
ogenic Bacteria," pp. 46-57. 



46 A MANUAL OF HYGIENE AND SANITATION. 

being benefactors rather than otherwise to the human 
race. 

The function of the saprophytic organisms is to break 
up dead organic matter into simpler chemical compounds 
and ultimately into end-products, such as carbonic acid, 
ammonia, and water, these latter substances being once 
more utilized in the nutrition of the higher forms of vege- 
table life, which are, in turn, necessary to the existence 
of animal life upon the globe. Indeed, it is only when 
the student of hygiene fairly realizes the great scope of 
the functions of these minute but almost omnipresent 
scavengers that he can comprehend the important part 
they play in the purification of our environment. In the 
air they possibly help the oxygen to destroy the harmful 
effluvia and exhalations of men and animals and the float- 
ing debris of organic substances; in the soil, the common 
receptacle of the wastes and refuse of vital activity, they 
quickly and continually convert these noxious additions 
into foods of the highest value to growing plants; in 
running streams and quiet pools they are of the greatest 
importance in the removal of the dangerous impurities 
washed from the surface of the land or recklessly dis- 
charged from human habitations, factories, and the like. 
And not only do the saprophytes help mankind in this 
way, but members of the class are beneficent in many 
others. For example, they enable those plants, the legu- 
minosse, which yield us the largest supply of vegetable 
proteids, to derive much of their nitrogen almost directly 
from the atmosphere; they have much to do with the 
flavor and value of dairy products, and new uses in 
which they may be employed in the domestic or commer- 
cial affairs of life are being announced from day to day. 
Thus we find this class of the bacteria, which comprises 



BACTERIOLOGY. 47 

by far the greater number of known species, to be our bene- 
factors and indispensable servanls both in preventing the 
accumulation of uoxious and harmful substances upon the 
earth and in really helping to produce the food which we 
eat and many things that we need or use in our daily life. 

The parasitic bacteria, on the other hand, have their 
habitat in or upon highly organized living matter, and 
exist at its expense. They also produce in their growth 
substances called toxins, that are either locally or gener- 
ally poisonous or harmful to the organism that is their 
host. It is needless to say that it is in this class that 
we find the disease germs, or pathogens, as some would 
call them. It should not be forgotttn, however, that the 
saprophytes, in the decomposition of complex organic 
bodies, may also produce ptomaines, more or less toxic 
to animal life. Of these latter we may instance as good 
examples the dangerous tyrotoxicon, a by no means 
uncommon product in the decomposition of milk or 
ice-cream, the cadaveric poison of the dissecting-room, 
etc. But though ptomaines may be more or less charac- 
teristic of the respective bacteria that produce them, each 
varies in its composition and properties according to the 
substance upon or in which it is produced, while the 
toxins are specific derivatives or " active principles" of 
their respective micro-organisms. 

Considering for the present the pathogenic bacteria 
alone, we are naturally brought to the discussion of the 
germ theory, which is, that the exciting cause of each 
contagious or infectious disease is some specific parasitic 
organism, and that these diseases are communicated only 
by the transferrence to and development of the particular 
parasite or germ within or upon the tissues of the infected 
individual. Consequently, such diseases are transmitted 



48 A MANUAL OF HYGIENE AND SANITATION. 

from one person to another, or, in some cases, from ani- 
mals to men or vice versa, by means of these micro- 
organisms, and the transference is by the air, water, 
food or other fomites, or by direct contact. It is evi- 
dent that, if facts and acquired knowledge establish the 
truth of this theory, the prevention of infectious diseases 
is greatly simplified and becomes merely a matter of 
combining effective sanitation, of which we have spoken, 
with the destruction of the specific exciting causes, i.e., 
disinfection. Nor is it essential that we any longer make 
the distinction between the terms contagious, infectious, 
zymotic and specific, that formerly obtained, since they 
may be practically used synonymously. The first of 
these terms used to be applied to those diseases which 
were thought to be transmitted most frequently by direct 
contact, and "infectious" to those in which the trans- 
mission was usually by fomites. But we know that 
germs of the former class may be transmitted by air, 
water, food, etc., and those of the latter by personal con- 
tact, though the reverse is what usually happens in the 
respective cases. The term "zymotic" was formerly 
applied to those diseases occurring in epidemics, and 
which were supposed to be due to fermentative processes; 
if used at all it should be given to any disease due to a 
living germ. The term " specific" should only be given 
to those maladies which have a specific origin — i. e., which 
have been proved to be due solely to a single organism. 

That all communicable diseases are due to such vegetal 
germs or kindred animal organisms is more than probable, 
and, while there are some for which it has not been fully 
proven, it is scarcely possible that any of these may arise 
from insanitary conditions without the presence of a living 
causative organism. 



BACTERIOLOGY. 49 

Our reasons for believing in the germ theory are based 
on empirical and logical facts as well as theoretical hypoth- 
eses. Leaving oat, at present, the scientific research work 
already done, it is evident that the matter that causes a 
disease — the contagium — must, when introduced into a 
susceptible person or animal, increase in quantity to an 
enormous extent. Note, for instance, the large amouut of 
actively virulent matter thrown off from a case of small- 
pox or scarlet fever, and yet how very little is required 
to initiate a disease. No dead chemical substance has the 
power of being increased to such an extent by simply find- 
ing a lodgement in a suitable medium. The poison of con- 
tagion, whatever it may be, evidently must have life and 
the power of reproduction. Moreover, these causes of 
disease, when freed from the body, may be carried long 
distances, and may still retain their power for harm for 
years, only waiting to find a suitable field before begin- 
ning to multiply and cause the same identical malady as 
before. Such causes must, therefore, be capable of enter- 
ing a state in which vitality is latent or dormant, and in 
which the reproductive functions are for a time inactive. 
But we do know that the spores of many bacteria, and 
sometimes the bacteria themselves, may be carried afar, 
kept long periods of time, and even exposed to con- 
siderable extremes of temperature, without being killed 
or losing their power of reproduction and rapid multi- 
plication. Again, we know that substances that are 
poisonous to or that prevent the development of these 
bacteria and kindred low forms of life, do, when properly 
applied or used, prevent or remove the danger of conta- 
gion and infection. 

There is also in the development and progress of any 
infectious diseases a direct analogy to the phenomena of 

4 



50 A MANUAL OF HYGIENE AND SANITATION. 

fermentation, whose causal ive organisms are of the same 
order as these which we are considering; the same rapid 
multiplication of cells in suitable media at proper tem- 
peratures, a period of incubation, and then changes in the 
infected body or host, which, after going on to a certain 
extent, check the further development and multiplication 
of the organism. What it is in the medium that checks 
the growth of the germ we may not be able to deter- 
mine a priori, but we may assume it to be something hos- 
tile to the contagium, as alcohol above a certain percent- 
age is deterrent to the further growth of the yeast-cell. 

Lastly, if the proof of Koch's postulates is essential to 
the acceptance of a given micro-organism as the cause of 
a given disease, we must believe, on the other hand, that 
a certain germ is a cause, if not the only one, of a certain 
malady if these postulates be proven about that germ in 
connection with the latter. 

To determine whether an organism is or is not patho- 
genic it is necessary to experiment on living animals. To 
do this we must use pure cultures of the organism and 
carry out all our processes, including inoculations and 
autopsies, under strictly antiseptic precautions. For ex- 
ample, we examine the blood and various tissues of a dis- 
eased animal microscopically; if bacteria be present in any 
of these, w T e make cultures from them, and if more than 
one kind of bacteria be present, the various kinds must be 
isolated and pure cultures made from each kind. When 
a pure culture is at last obtained it may be studied both 
microscopically and as to its characteristics in various 
media and at different temperatures. Finally, healthy 
animals known to be susceptible to the disease are inocu- 
lated from the pure culture, and, after the period of incu- 
bation, carefully watched for symptoms of the disease in 



BACTERIOLOGY. 51 

question. Should these manifest themselves, the animal 
is killed and the blood and tissues carefully examined for 
the inoculated organisms. 

The postulates of Koch, which are necessary to prove 
that a germ is the cause of a given disease, are : 1. The 
micro-organism must be found in the blood, lymph, or 
diseased tissues of a person or animal sick or dead of the 
disease. 2. The micro-organism must be isolated from 
the blood, lymph, or tissues and cultivated in suitable 
media outside of the animal body. These cultivations 
must be carried on through several generations until a 
pure culture of the germ is obtained. 3. A pure culture 
thus obtained must, when introduced into a healthy and 
susceptible animal, produce the disease in question. 4. 
In the inoculated animal the same organism must again 
be found. 

In the case of many diseases peculiar to human beings 
alone the third condition must remain undetermined and 
our chain of proof be broken, because we should not 
endanger human health or life by our inoculations. But 
in diseases common to men and animals the experiments 
necessary can be completely carried ont, and where a 
germ cau be proved to be the cause, according to these 
postulates, of the malady in animals, we can also fairly 
conclude that it is the cause of the same disease in human 
beings. The specific germs of a number of maladies com- 
mon to man and beast have thus been determined, together 
with those of a large number of affections peculiar to ani- 
mals alone. 

After infection or the reception of the contagium by a 
susceptible animal or person there is a period of incuba- 
tion before the manifestation of the characteristic symp- 
toms of the disease. This period is variable according 



52 A MANUAL OF HYGIENE AND SANITATION. 

to the disease or kind of germ, and during it the micro- 
organisms rapidly increase in numbers and their consequent 
power for evil. 

After the pathological process is well under way we shall 
probably find one of two conditions existing, viz., that 
" in which the blood is the chief field of activity of the 
organisms," 1 and the vessels of the victim are swarming 
with the microbes — in other words, a true septicemia ; or 
else one where " the poisonous results are not necessarily 
accompanied by the growth of organisms in the tissues," 
these latter, in all likelihood, not extending beyond the 
lymphatic glands nearest to the point of inoculation — i. e., 
a toxcemia. A good example of the former condition is 
furnished by a case of anthrax or of pyaemia, and of the 
latter in diphtheria. However, we shall find in either 
condition that if we isolate the peculiar product or toxin 
of the specific germ, either from artificial growths upon 
or in culture media, or from the blood or tissues of an 
animal sick or dead of the disease, and inoculate this into 
a susceptible animal, the general symptoms and results 
produced are practically the same as in an ordinary case 
of the disease. This goes to prove that the products of 
pathogenic bacteria are toxic in character and poisonous 
to the tissues, either locally or generally; that each of 
these toxic products gives rise in susceptible animals to 
characteristic symptoms which, taken together, indicate 
a specific disease, and that infection must be accordingly 
a chemical and toxicological process. Another point to 
note just here is that these toxins are apparently harmful 
to the bacteria themselves whenever they exceed a certain 
amount, as is shown by the fact that most of the infectious 

1 Abbott, loc. cit. 



BACTERIOLOGY. 53 

diseases are self-limiting, and by the cessation of growth 
and even the death of the germs in the various culture 
media after a certain length of time. It is but right to 
state, however, that there is another possible explanation 
of this latter phenomenon, viz., an increase in the resist- 
ance of the infected body to the action of the germs and 
toxins, or, as iu the case of culture media, the marked 
change in reaction caused by the bacterial products. 

Having thus obtained some knowledge of the exciting 
causes of contagious diseases and of how they act, one of 
the most important considerations is in relation to the 
prevention of the incurrence of these diseases by the well, 
aud to the antagonizing or checking of the further action 
of the cause in those already infected. It is well to dis- 
infect and to destroy disease germs whenever and wherever 
it is possible to do so, but it will be still better so to 
strengthen and fortify the human body that the microbes, 
even though received into it, will be unable to attack it 
or do it harm. That we have the means of producing 
such immunity in the case of one disease, at least, is well 
shown by the history of vaccination, and the abundant 
work of numerous investigators in recent years indicates 
that the promise of similar results in regard to many other 
maladies is by no means vain. Certain it is that many 
human beings and animals have been rendered apparently 
immune to other fatal diseases, and the indications point 
to the probability that the human race will shortly have 
the same protection against most of the transmissible 
maladies that it now has against smallpox. 

With the knowledge that immunity to infectious dis- 
eases may be produced either accidentally or intention- 
ally, and may be practically applied without a complete 
understanding thereof, we need not consider the method 



54 A MANUAL OF HYGIENE AND SANITATION 

whereby the body brings about such immunity. Never- 
theless, several theories have been advanced in the attempt 
to explain the phenomenon. Of these two have been prac- 
tically disproved, viz., the exhaustion theory of Pasteur, 
which was that the pathogenic germs in their process of 
growth in the body removed some material from the latter 
necessary to their existence; and the diametrically oppo- 
site retention theory of Chauveau, which was that the 
germs produced some substance which gave immunity 
as long as it was retained in the tissues. On the other 
hand, there are strong adherents to both the phagocy- 
tosis theory of Metchnikoff and the humoral theory of 
Biichner. 

The phagocytosis theory is u that immunity against 
infection is essentially a matter between the invading 
bacteria on one hand and the leucocytes of the tissues 
on the other; that during the first attack of the disease 
the white blood-corpuscles gain a tolerance to the poisons 
of the bacteria, aud so are able to resist the next incur- 
sions of the enemy and to actually attack and destroy the 
latter/ ? Biichner has apparently shown that the blood- 
plasma, especially that of immune animals, is actually bac- 
tericidal to many virulent germs, and he attributes this 
effect to the presence in the fluid of certain proteid sub- 
stances akin to globulin. These he terms alexins, from a 
Greek word meaning to protect. Further, he believes that 
they act chemically in causing the death of the disease 
germs, and that the increased amount of alexins in the blood 
of those who have acquired immunity is brought about by 
a stimulation or " reactive change 7 ' in certain cells due to 
the presence of the bacteria or their products. Moreover, 
this humoral theory serves to account for the natural 
immunity possessed by some individuals and animals, their 



BACTERIOLOGY. 55 

body juices presumably containing, through some cause 
or other, an extra quantity of the protective proteids. 

There is, however, another theory — that of the anti- 
toxins — which, in view of recent developments and the 
fact that it is the most capable of immediate practical 
application, is probably the most important of all. It is 
well known that the human system has the power of 
tolerating or accommodating itself to the action of almost 
any toxic substance — provided the latter be administered 
at first in sufficiently minute doses and then gradually in- 
creased — until it can in time withstand quantities that 
would quickly prove fatal to one uuaccustomed to the 
poison. Ehrlich has further shown that, with the toxic 
alkaloids of certain higher plants, after a certain degree 
of tolerance is attained the administration of the drug may 
be much more rapidly increased, and that while up to this 
point no apparent change occurs in the body fluid, now, 
when the tolerance becomes so much exaggerated, a new 
substance is produced and found in the blood which is 
capable of neutralizing the poison in not only that indi- 
vidual, but also in others into whom it may be introduced. 
Many experiments have shown that this same production 
of antidotal or antagonizing substances may be brought 
about by the slow administration of the toxins of patho- 
genic bacteria — something not hard to understand when we 
remember that the bacterial toxins are just as much the 
products of plant life as are the alkaloids that Ehrlich used, 
and very much like the latter in formula or composition. 

On the other hand, the antitoxins, as these new sub- 
stances antidotal to the toxins are called, have been found 
to be albuminoid in character and similar to the nucleins. 
In fact, some attempts have been made to employ the 
latter in place of or in conjunction with the autitoxins, 



56 A MANUAL OF HYGIENE AND SANITATION. 

with results which have not been altogether without success 
and to which reference may hereafter be made. 

Much credit must be given to the labors of Behring, 
Roux, Kitasato and others for the development of prac- 
tical methods of using the antitoxins, methods which are 
now recognized as eminently proper and even superior to 
any others in the treatment of some of the most virulent 
diseases. The great reduction in the mortality from one 
disease alone — diphtheria — already attained through the 
application of this treatment almost exceeds expectation 
and belief, and the promise seems now to be that the 
results with respect to cholera and other deadly maladies 
will be equally brilliant and add further glory to this new 
science of bacteriology. 

To some it may seem that either the humoral or the 
antitoxin theory is identical with the discarded retention 
theory of Chauveau; but it should be noted that, accord- 
ing to the latter, the invading microbes themselves 
produce the antidote or antagonizing substance, while 
Biichner ? s theory attributes this production to the inte- 
gral cells of the body, which furnish the alexins normally 
in minute quantities to the blood, and insists that the 
latter are germicidal to the bacteria themselves; and, on 
the other hand, the antitoxins, though produced by body 
cells like the alexins, act chemically in neutralizing the 
bacterial poisons, and are dependent upon the prior pres- 
ence in the body of the toxins and are a result of its 
acquired tolerance to the latter. With alexins or anti- 
toxins it is evident that the immunity will last as long as 
these substances remain unchanged in the blood. 

Nor is there any reason why the phagocytosis, humoral, 
and antitoxin theories should not mutually support rather 
than tend to discredit one another. There seems to be 



BACTERIOLOGY. 57 

good evidence of the phenomena upon which each of the 
three is based, and, even with our present incomplete 
knowledge of the blood and its component parts, it is 
not difficult to conceive that while the alexins, and later 
the antitoxins, protect the leucocytes by respectively 
weakening the vitality of the microbes and neutralizing 
their products, the leucocytes, thus guarded and in full 
vigor, attack and make way with the bacteria, which 
have lost their virulence and power for evil. In other 
words, if the production of the toxins of an infectious 
malady is not too rapid, all three of these agents may 
combine to overcome the enemy and not only to limit the 
disease but also to give subsequent immunity for a more 
or less prolonged period. 

Nevertheless, experience will continue to show that, 
whether one or all of these theories may be finally 
accepted or whether other methods by which the body 
protects itself may be discovered, sanitation and a con- 
dition of perfect health throughout the system are of the 
utmost importance in warding off attacks of or securing 
immunity from any of the pathogenic organisms, and in 
withstanding their ravages, should disease be incurred. 
A sound body, therefore, is a most vitally active and not 
simply a passive agent for the prevention of such diseases. 

Within a comparatively short space of time the anti- 
toxins have been discovered, tried, and apparently prac- 
tically adopted by the medical profession of the civilized 
world as a safe and efficient means for the prevention or 
the alleviation and cure of several of our most dreaded 
diseases. A short account of the usual method of pre- 
paring the antitoxin of diphtheria will, therefore, prob- 
ably not be uninteresting. 

In the first place, it is necessary that the toxin of the 



58 A MANUAL OF HYGIENE AND SANITATION 

disease should be produced, which is commonly done 
by growing the specific organism in a peptone-bouillon. 
When this has attained a powerful and definite virulency, 
as' determined by its effect on small animals of known 
weight, the organisms are destroyed by some germicide, 
such as trikresol, or, more commonly, are removed by a 
careful filtration from the bouillon which holds the toxin 
in solution. A small quantity, say one cubic centimetre, 

Fig. 10. 




Filter for removing bacteria from fluid culture media. 

of the filtered bouillon is then injected into a large animal, 
such as the horse, which should be in good health and, 
preferably, should have been tested previously by inocu- 
lations of tuberculin and mallein to eliminate the possi- 
bility of the presence of tuberculosis or glanders. The 
animal manifests the disturbances peculiar to the disease 
in question for a few days, but usually in a minor degree, 
since the dose was purposely quite small in proportion to 
its weight; as soon as recovery is evident auother inocu- 
lation of an increased dose is made, and so on until ex- 



BACTERIOLOGY. 59 

perirnent shows that the animal can withstand practically 
an unlimited quantity of the toxic bouillon, and certainly 
an amount which would have been quickly fatal before the 
first inoculation. This is evidence that the antitoxin has 
been produced and exists in approximately sufficient 
degree in the blood- serum. A quantity of blood is then 
taken with the strictest antiseptic precautions from the 
jugular or other large vein of the animal, the latter returned 
to its quarters, and the blood set aside on ice to coagulate. 
This done, the clear serum containing the antitoxin is 
drawn off and to it is added a small quantity of trikresol 
or other harmless preservative. 

Fig. 11. 



Roux aseptic hypodermic syringe for administering antitoxin. 

It is now necessary to determine the strength of the 
serum. The fatal dose of toxin for guinea-pigs is readily 
found by experiment. Behring, therefore, suggested in 
the case of diphtheria antitoxin that the immunizing unit 
be taken to be 1 c.c. of a serum of which 0.1 c.c. would 
prevent oedema and death in guinea-pigs when injected 
simultaneously with ten times the fatal dose of the toxin. 
In other words, the immunizing unit was to be sufficient 
to overcome one hundred times the amount of the toxin 
required to kill a guinea-pig. 

The antitoxin serums now administered are, however, 
much stronger than this normal serum of Behring' s, 10 
c.c, the amount usually injected, being equivalent to 
from 600 to 2500 or even more immunizing units, the 
weaker strength being used for immunizing those who 
have not as yet incurred the disease. Much depends 



60 A MANUAL OF HYGIENE AND SANITATION 



upon the early use of the specific antitoxin in cases of 
diphtheria, and probably also in the other diseases for 
which this method of treatment will be found valuable. 
It is not to be supposed that the remedy has any power 
to repair the organic lesions which have been caused by 
the action of the powerful toxins. That the antitoxin 
treatment is invaluable cannot be doubted. The statis- 
tics of Prof. Welch, of Johns Hopkins Hospital, founded 
on a very large number of diphtheria cases, " show an 
apparent reduction of case-mortality of 55.8 per cent.," 
and where the application was made in the first three 
days of the disease the mortality was only 8.5 per cent, 
in over 1100 cases as against a mortality of 30 per cent, 
or more under former methods of treatment. Another 
interesting report is that of the Chicago Department of 
Health for 1896. In that city in that year there were 
2436 cases of true diphtheria verified bacteriologically. 
The antitoxin was administered to 2302 of these, with a 
resultant mortality of only 6.56 per cent., or 151 deaths. 
Moreover, 2016 other persons exposed to the disease were 
inoculated with the antitoxin in order to immunize them, 
and of these only 14 subsequently contracted the malady, 
and none died. Further comment seems unnecessary. 

Another practical method of securing immunity, advo- 
cated and employed by several noted investigators, is as 
follows : To produce, by cultivating the pathogenic bac- 
teria under abnormal conditions, toxins of much less than 
normal virulence, and then, after filtration or steriliza- 
tion of the culture medium in order to remove or destroy 
the causative microbes, to make a series of inoculations of 
progressively increasing strength, and thus directly bring 
about a state of accommodation to or protection against 
the germ and its toxin without serious risk to the subject. 



CHAPTER III. 

THE ATMOSPHERE — AIE. 

The composition of the atmosphere surrounding the 
earth is remarkably uniform. It is practically always 
the same everywhere, provided no obstacle be interposed 
to the action of those natural forces by which this uni- 
formity is maintained. This atmosphere is estimated to 
be about forty miles in depth, and its weight- pressure, 
of which we have a visible manifestation in the action of 
the barometer, upon the total surface of the adult human 
body is equivalent to that of about fourteen tons. Any 
considerable variation in this pressure may give rise to 
disturbances of health more or less serious, such as the 
cardiac derangements and "mountain sickness" experi- 
enced by strangers visiting high altitudes, or the " caisson 
disease " of those who work in a compressed atmosphere. 
In fact, it is not improbable that some of the vague dis- 
turbances of comfort to which a large class of persons are 
subject during changes of the weather will hereafter be 
found to be due to the variations in this pressure which 
are constantly occurring everywhere. 

The average composition of the air in its normal state 
is about as follows : Oxygen, 20.96 per cent, by volume; 
nitrogen and argon, 79 per cent.; carbon dioxide, 0.04 
per cent.; aqueous vapor, varying in amount with the tem- 
perature and other conditions; a trace of ammonia, and a 
variable amount of ozone, organic matter, sodium salts, etc. 



62 A MANUAL OF HYGIENE AND SANITATION. 

The variation in the percentage of oxygen may be from 
20.87 in towns to 20.98 in pare mountain air or far out at 
sea; in the percentage of C0 2 , from 0.02 to 0.05. So far 
as we know at present, the nitrogen variation is almost in- 
finitesimal. The air is a mechanical, not a chemical 
mixture, and there is always some change taking place 
in the proportions of the various constituents. However, 
the mixture is maintained in its wonderful uniformity by 
the interdependent action of plants and animals, and by 
the diffusion of gases, the law of which is that " a gas 
expands into a space in which there is another gas as 
freely and as rapidly as if there were a vacuum." 
Though this agency, like the other, is continually oper- 
ating, its results are greatly facilitated by adventitious 
air-currents and by the application of heat. When a gas 
is thus diffused it will not separate again from the others 
under ordinary circumstances. 

Oxygen is the most important of the above constitu- 
ents. It supports all animal life; oxidizes, destroys, and 
renders harmless organic impurities) and, by oxygenating 
the blood and oxidizing the food for our tissues, gives us 
heat and energy, the vital source of all our thoughts and 
actions. The supply to the atmosphere is constantly 
maintained by the higher plant life, which decomposes 
carbon dioxide and gives off oxygen to the air. In man 
the greatest limit of life without oxygen or air is about 
four minutes. A decrease in the proportion of oxygen 
in the air does not manifest itself by untoward symptoms 
until there is less than 13 per cent, by volume; then, as 
it falls lower and lower, the respirations become slower, 
deeper, and more difficult, less oxygen is absorbed by the 
blood, and there follow dyspnoea, asphyxia, and death. 
This may occur within a short time when the percentage 



THE ATMOSPHERE— AIR. 63 

goes below 8 per cent., and fatal asphyxia supervenes very 
rapidly when there is as little as 3 per cent, of oxygen. 

The main function of the nitrogen of the atmosphere 
seems to be to act as a diluent and to prevent the too 
energetic action of the oxygen. We know now, however, 
that, by the aid of certain bacteria, at least one family of 
plants — the leguminosse — is able to take nitrogen almost 
directly from the air and to store it up for animal use in 
the form of proteids. The ammonia ever present in the 
air is also a source of nitrogen food for some plants. 

The gaseous element, argon, recently discovered by 
Lord Rayleigh and Prof. Ramsay, comprises about 1 per 
cent, of what has heretofore been considered atmospheric 
nitrogen. Thus far little is known concerning it except 
that its atomic weight is probably somewhat less than 40, 
its density about 20 and that it is very inert, though 
Berthelot has succeeded in making it combine with 
nascent vapors of benzene under the influence of an elec- 
trical discharge. That it is a constant component of the 
atmosphere for some definite purpose is more than prob- 
able, but what this purpose may be is as yet unknown. 

The carbonic acid present in the atmosphere is of no direct 
use to animals, but is essential to the support of vegetable 
life, furnishing the carbon necessary for the formation of 
the carbohydrates and proteids, which are, next to water, the 
main constituents of plants. The proportion of carbonic 
acid in the out-door air varies somewhat from time to time, 
owing to the changing conditions. It is washed out of the 
air by rain, and there is, therefore, less after a heavy storm ; 
plants absorb it by day, and some give off a slight quan- 
tity of it by night, the strata of the atmosphere near the 
ground receive an excess of it from the soil-air; it is a 
constant product of combustion and of the decomposition 



64 A MANUAL OF HYGIENE AND SANITATION. 

of organic matter by saprophytic bacteria, etc. Though 
heavier than air, it is comparatively evenly distributed 
through the atmosphere by the force of diffusion. 

The normal proportion in the atmosphere varies from 
0.02 per cent, to 0.05 per cent., but we may take the 
average to be about 0.04 per cent. Should, however, 
any important tests of the amount in-doors be required, 
the percentage in the out-door air at that particular time 
and place should also be determined for the sake of accu- 
racy. Within the limits just given the carbonic acid 
cannot be considered as an impurity of the atmosphere, 
for it is ever present in the air, and is as necessary to 
plant life as oxygen is to animals. It is derived from 
the combustion of carbonaceous materials, from the ex- 
halations and excretions of animals and men, and, as was 
indicated, in large measure from the action of the sapro- 
phytic bacteria and also of the budding fungi upon organic 
matter. Moreover, any excess above the normaj percent- 
age as given is to be regarded not so much as an impurity 
as an indication that certain processes are at work, wjiich, 
by their other products, may make the air impure and 
unsafe for human use. 

The amount of aqueous vapor in the atmosphere varies 
constantly because the factors governing it — condensation 
and evaporation — are constantly in action, these depend- 
ing, of course, mainly upon the continual variations in 
temperature. There is probably never a perfectly dry 
air, unless it is made so artificially, and precipitation 
occurs the moment the degree of complete saturation is 
exceeded. The range of relative humidity is probably 
from 30 to 100 per cent., this being equivalent, accord- 
ing to the temperature, to a water content of from one 
to twelve or fourteen grains to the cubic foot of air. 



THE ATMOSPHERE— AIR. 65 

The best proportion for health has not been experiment- 
ally determined, but is generally considered to be from 
65 to 75 per cent, when the temperature is moderate. 1 

In all normal air there is at least a trace of ammonia, 
either free or combined, a small amount of the salts of 
sodium (especially near the sea) and of other minerals, 
and a trace of organic matter. This last is part of the 
animal and vegetable debris of the earth; when it rises 
above a trace it is to be treated as an impurity, as should 
any excess of ammonia. 

Minute particles of almost every substance known are 
being constantly thrown off into the atmosphere, and it is 
only the unceasing action of nature's purifying powers 
that keeps the proportion within the limits of safety to 
the human race. Solid particles, lifted up by the winds, 
fall to the earth again, or, if organic, are partially oxi- 
dized and decomposed by the oxygen and ozone. The 
gases are diluted and diffused so as to be no longer harm- 
ful, or are decomposed, or are washed back to the earth 
by rain or snow. The great volume of carbonic acid is 
kept within bounds by the action of the vegetable world. 
The natural purifiers of the atmosphere, therefore, are 
the force of gravity, diffusion, dilution by the air itself, 
winds, oxidation, rain, and the action of plant life; and 
so exactly are these related to their work that never, 
when they have fair opportunity to act, does the compo- 
sition of the air vary much from the normal for any great 
length of time. 

The impurities in the atmosphere that are especially 
liable to have a deleterious influence upon health may be 

1 When the temperature is upward of 80° F. a humidity of but little over 70 
per cent, may be very uncomfortable and depressing if the air is still and evap- 
oration from the body surface thus impeded. A breeze makes even a higher 
humidity less noticeable. 

5 



QQ A MANUAL OF HYGIENE AND SANITATION 

classed as follows : 1. Suspended matters. 2. Gaseous 
and semi-gaseous substances, including: 3. Those espe- 
cially due to respiratory, combustion, and decomposition 
processes and which are particularly liable to contaminate 
the air of dwellings or inhabited apartments. 

The most important suspended matters are sand, dust, 
soot, pollen of various plants, micro-organisms of all kinds, 
particles of epithelia, and other excreta thrown off from 
animal bodies, and dusts or finely divided substances 
characteristic of certain trades or industries. These may 
do harm by clogging up the air-vesicles of the lungs 
and thus obstructing respiration, though it is doubtful 
whether their action is ever only so mild or simple; by 
their irritant action upon the respiratory passages; by being 
in themselves poisonous or hostile to the system, or, as in 
the case of micro-organisms, by the power they have in 
the causation of disease. Such germs may lodge in the 
respiratory passages to do their harm, or may be swal- 
lowed and so cause maladies, such as typhoid fever or 
cholera, which primarily affect the digestive tract. 

It is, however, questionable whether pathogenic organ- 
isms, especially the bacteria, are commonly to be found 
dissociated from other substances floating in the air. Ex- 
periments by Cornet and others seem to show that such 
microbes are more apt to be adherent to dust particles, par- 
ticularly those of organic nature, and it is probable that free 
bacteria in the out-door atmosphere could not long main- 
tain their vitality deprived of nutriment and exposed to 
the action of light and oxygen. Beside, they are so 
quickly diluted and reduced in numbers in proportion to 
any reasonable volume of air, that the occasions must be 
rare indeed when they could there cause disease. In- 
doors, especially where ventilation is neglected, the case 






THE ATMOSPHERE— AIR. 67 

is different, and there is no doubt that the air frequently 
becomes the carrier of the dangerous pathogens. 

We must also make a distinction as to whether the 
other solid impurities are found in the out-door air or in 
enclosed spaces; and, if in the latter, whether in healthy 
dwellings, in sick-rooms and hospitals, or in workshops 
and factories. Out-of-doors, dust, sand, soot, pollen, waste 
dirt from dwellings, street refuse and the remains of 
plant and animal life will predominate; in-doors the par- 
ticles will be more limited in variety, but not in impor- 
tance. Among them will be epithelium and other cells, 
possibly pus-corpuscles, hair, bits of clothing, upholstery, 
food, etc. One might also find arsenical or other poi- 
sonous dnst from wall-paper or paint. In sick-rooms and 
hospitals there will probably be pus-cells, mycelia, bac- 
teria, etc. Mills, factories, and mines have their special 
atmospheres filled with particles peculiar to the materials 
or occupation, which have a marked effect for harm, in 
many cases, on the health of the workers. 

The gaseous and semi-gaseous impurities of most im- 
portance are those resulting as products of human respira- 
tion and cutaneous exhalations, as products of combustion, 
peculiar gases from sewer-air or soil-air, organic emana- 
tions and vapors from decomposing animal and vegetable 
matter, and the volatile substances that characterize the 
various atmospheres in and about gas-works, factories, 
and other industries. Chemically, they may be classified 
as the various compounds of carbon and of sulphur with 
oxygen or hydrogen, and as ammonia compounds, volatil- 
ized minerals and mineral acids, and many gaseous and 
semi-gaseous matters of organic nature but indeterminate 
composition. 

Inasmuch as certain of these impurities, viz., human 



68 A MANUAL OF HYGIENE AND SANITATION. 

exhalations, combustion products, and not infrequently 
the so-called sewer-gas, are particularly liable to be 
found together as contaminants of the atmosphere of 
inhabited rooms and dwellings, it will be advisable to 
consider them in a class by themselves, and to study 
their effect upon health, both collectively and singly. 
The volatile excreta from the lungs and skin are carbonic 
acid, aqueous vapor, and a considerable amount of nitrog- 
enous organic matter, to which the term " crowd-poison ?? 
is sometimes given. As products of combustion from the 
ordinary lighting and heating apparatus of dwellings we 
may have carbonic acid (dioxide), carbonic oxide (mon- 
oxide), sulphur dioxide, ammonia (with possibly its sul- 
phide), and aqueous vapor. Of sewer-gas and soil-air 
we shall speak later. 

Carbonic-acid gas, contrary to the general opinion, can- 
not be said to be directly poisonous or harmful to health 
in the proportions in which it is likely to be found in 
any dwelling or inhabited apartment. Although present 
to the extent of not over 0.05 per cent, in normal out- 
door air, numerous experiments indicate that both men 
and animals may inhale much larger proportions than 
this without apparent harm, provided the percentage of 
oxygen in the air be maintained at or above the normal; 
an increase of the carbonic acid from other sources than 
respiration and combustion seems to have no appreciable 
effect upon the system until it reaches more than 2 per 
cent., and many work daily in atmospheres containing 
almost this amount as a result of their peculiar occupa- 
tions. Dyspnoea does not begin to occur, and then 
only in some, until the percentage goes above 3 or 4 per 
cent. In quantities above these figures there is much 
difference of opinion as to the effect of the gas upon the 



THE ATMOSPHERE— AIR. 



69 



human economy, and the writer is not aware that it has 
ever been determined beyond question as to just what 
percentage is fatal. Prof. Parkes states the lethal pro- 
portion to be from 5 to 10 per cent.; while another states 
that animals may be kept for a long time in an atmos- 
phere in which there is a high percentage of carbon 
dioxide, provided the percentage of oxygen be increased 
at the same time. Dr. Hime says that " it may be 
assumed that 10 or 20 per cent, is a dangerous amount," 1 
but Wilson 2 shows that air having from 25 to 30 per cent, 
may be inhaled with impunity. It is to be understood 
that the above percentages are all by volume. 

According to his size, an adult man at rest absorbs from 
fifteen to eighteen cubic feet of oxygen and exhales from 
twelve to fourteen cubic feet of carbonic acid in twenty- 
four hours. Reich ert 3 says : u The amount of O varies 
from 600 to 1200 grammes (15 to 30 cubic feet) per diem, 
and that of C0 2 from 700 to 1400 grammes (12.5 to 25 
cubic feet) — approximate averages being about 750 
grammes of O and 875 grammes of C0 2 ." The mini- 
mum excretion may, therefore, fairly be taken to be 
about seven-tenths of a cubic foot of carbonic acid for 
adult men and six-tenths of a cubic foot for women, or 
for each person of a mixed assemblage. Now, it is evi- 
dent that it would require many hours before a room of, 
say, 1000 cubic feet capacity would lose enough oxygen 
to or gain sufficient carbonic acid from a single adult 
occupant to produce even the slightest apparent harmful 
results upon him, even though any ingress of fresh air 
were absolutely prevented; and yet experience tells us 



1 Stevenson and Murphy, vol. i., p. 945. 

2 American Journal of Pharmacy, 1893, p. 561. 

3 American Text-book of Physiology, p. 536. 



70 A MANUAL OF HYGIENE AND SANITATION. 

that the atmosphere of such a room will become exceed- 
ingly foal and actually detrimental to health long before 
the lapse of time necessary to exhale sufficient carbonic 
acid to induce any serious effects. Moreover, carbonic- 
acid gas is odorless, while the air of inhabited, unventi- 
lated rooms is characterized by a decidedly offensive smell 
that remains for some time, even after adequate ventila- 
tion has been secured and when chemical tests show the 
percentage of carbonic acid to have been reduced to 
nearly the normal. u The chemical analyses of the air 
of overcrowded rooms, and the experiments upon animals 
made by many investigators, indicate that the evil effects 
observed are probably not due to the comparatively small 
proportions of carbonic acid usually found under such 
circumstances. . . . The proportion of increase of 
C0 2 and of diminution of oxygen which has been found 
to exist in badly ventilated churches, schools, theatres, 
etc., is not sufficiently great to, satisfactorily account for 
the great discomfort which such conditions produce in 
many persons, and there is no evidence that such an 
amount of change in the normal proportion of these gases 
has any influence upon the increase of disease and death- 
rates which statistical evidence has shown to exist among 
persons living in crowded and un ventilated rooms.' 71 

Therefore, it must be something other than carbonic 
acid that dangerously pollutes the air of our dwellings and 
necessitates the provision of some system of ventilation. 
However, with our present knowledge, we cannot say that 
a diminution of oxygen and an increase of carbonic acid 
in the atmosphere which one breathes habitually does not 

1 "The Composition of Expired Air and its Effect upon Animal Life," Drs. 
Mitchell, Billings and Bergey, No. 989, vol. xxix., Smithsonian Contributions to 
Knowledge. 



THE ATMOSPHERE— AIR. 71 

tend to lower the general tone and perhaps the bactericidal 
powers of the body, and thus to render it more susceptible 
to deleterious influences; and there is some evidence that 
as the carbonic acid in the atmosphere increases there is 
a lessening of the amount of this gas excreted from the 
body; so that, on general principles, it will be always 
wiser to use every reasonable means to maintain the nor- 
mal proportion of the various gases in the atmosphere. 

Aqueous vapor is another of the substances excreted 
continually from both the lungs and the skin, but it is 
obvious that, in itself, it cannot be directly harmful to 
the system, for we find it ever present in all natural 
atmospheres, and are continually replacing its loss from 
our bodies by imbibition. The quantity daily thrown off 
from the lungs and skin will depend on the temperature 
and humidity of the atmosphere, the quantity of air in- 
spired and water imbibed, and many other factors, but 
under ordinary conditions the average excretion will be 
from 100 to 1700 grammes (about 3.5 to 60 fluidounces), 
though increased exertion might cause even the latter 
amount to be greatly exceeded, It is accordingly possible 
that this large quantity of moisture, tending to saturate 
an atmosphere already humid, might act indirectly upon 
the system by preventing evaporation from the skin, and 
thus reflexly checking the excretion of the waste matters 
by the sweat-glands, the retention of these wastes in the 
system probably helping to produce the depression, head- 
ache, and other symptoms experienced by those breathing 
foul air. It has been noticed that these symptoms due to 
foul air are more readily manifested when the temperature 
of the atmosphere is much below or much above the usual 
room-temperature of 65° to 70° F. At low temperatures 
it is easy to saturate the air, and beside, the excreting 



72 A MANUAL OF HYGIENE AND SANITATION. 

action of the skin is much lessened by the cold; at high 
temperatures the humidity is often already near the satu- 
ration-point, while the external heat tends to increase the 
quantity of water given off by the lungs and skin. "At 
high temperatures the respiratory centres are affected 
where evaporation from the skin and mucous surfaces is 
checked by the air being saturated with moisture — at low 
temperatures the consumption of oxygen increases, and 
the demand for it becomes more urgent." 1 At 70° F. 
the aqueous vapor from an adult body would in an hour 
or less completely saturate from 350 to 600 cubic feet of 
air having the not unusual relative humidity of 75 per 
cent., while at 80° F. an equal or even greater volume 
would doubtless gain its maximum of moisture from the 
increase of perspiration due to the extra heat. Moreover, 
as evaporation of the perspiration is one of the most im- 
portant means for maintaining the balance between heat 
production and heat dissipation, interference with this 
process naturally tends to rapidly raise the body-tempera- 
ture and produce the consequent effects upon its nervous 
mechanism. 

The third contaminant given to the air from human 
bodies is an indefinite volume of offensive organic matter, 
and until quite recently this has been looked upon as by 
far the most harmful part of animal exhalations. But 
lately a number of experiments by various investigators 
have seemed to indicate that this organic effluvium is not 
so dangerous as it has hitherto been considered and that 
part, at least, of the symptoms due to air vitiated by respi- 
ration is to be attributed to the conditions already men- 
tioned, viz., a decrease of oxygen and an increase of 

1 Drs. Mitchell, Billings and Bergey, loc. cit. 



THE ATMOSPHERE— AIR. 



73 



carbonic acid, heat and moisture. It is also doubtful 
whether much, if any, of this organic matter comes from 
the lungs of healthy persons. " In ordinary quiet respira- 
tion, no bacteria, epithelial scales, or particles of dead 
tissue are contained in the expired air. . . . The 
cause of unpleasant, musty odors in rooms may in part be 
due to volatile products of decomposition from decayed 
teeth, foul mouths, or disorders of the digestive apparatus, 
and in part to volatile fatty acids given off with or pro- 
duced from the excretions of the skin, and from clothing 
soiled with such excretions/' 1 However, whatever may 
be the exact source of this contamination, we know this 
concerning it — that it is decidedly offensive to the sense 
of smell, that it is organic and nitrogenous, yielding am- 
monia, darkening sulphuric acid, decolorizing perman- 
ganate of potash, and rendering offensive pure water 
through which the vitiated air has been drawn. Moreover, 
it must in fairness be stated that, in spite of the later 
experiments, it has seemed to such careful investigators 
as Brown-Sequard, D' Arson val, Merkel and others to 
be directly poisonous to lower animals. In general, it is 
given off proportionately with the carbonic acid from the 
body, though this rule is not infallible; it is apt to be 
unevenly distributed throughout the atmosphere of the 
apartment and is probably, therefore, not truly gaseous, 
but more like an impalpable dust; it oxidizes but slowly, 
beino evident for some time after fresh air has been 
admitted and the carbonic acid has been almost reduced 
to the normal, and, while neither condensed nor dissolved 
in the aqueous vapor from the body, it is especially at- 
tracted and retained by hygroscopic substances, such as 



1 Drs. Mitchell, Billings and Bergey, loc. cit. 



74 A MANUAL OF HYGIENE AND SANITATION. 

wool, paper, feathers, etc. Its smell is generally per- 
ceptible when the respiratory carbonic acid reaches 0.03 
or 0.04 per cent., sometimes before this point is reached, 
especially in sick-rooms or hospital wards, and is decidedly 
offensive when the total carbonic acid approaches 0.1 per 
cent. 

The most important of the imparities resulting from 
the combustion of coal, the principal fuel substance used 
in towns and cities, are soot and tarry matters (to the ex- 
tent of about 1 per cent, of the coal consumed), carbon 
monoxide and dioxide, aqueous vapor, and more or less 
ammonium sulphide, carbon disulphide, hydrogen sul- 
phide, sulphur, sulphur dioxide and sulphuric acid. The 
relative amounts of the oxides of carbon — as well as 
of the other gases — will depend upon the perfection of 
combustion; " but it has been calculated that for every 
ton of coal burnt in London something like three tons of 
carbon dioxide are produced/' and as that city's coal 
consumption is over 30,000 tons per diem, we can see 
that its atmosphere must receive the enormous daily con- 
tamination of about 300 tons of soot and 90,000 tons of 
carbonic acid. No wonder they have an occasional fog 
there ! 

The combustion products of wood are in the main 
simply carbon monoxide and dioxide, and water, while 
those of coke and of gas are practically the same as of 
coal. From our heating apparatus, if properly constructed 
and arranged, these products pass off almost directly to 
the exterior of our dwellings and are rapidly dissipated 
in spite of their excessive volume, for " diffusion and the 
ever-moving air rapidly purify the atmosphere from car- 
bon dioxide," and, in fact, from the others also, with the 
exception of the soot and tarry products. 



THE ATMOSPHERE— AIR. 



75 



Should, however, combustion be incomplete, or should 
the stoves or other heating apparatus be imperftct, the 
gases may seriously or even dangerously contaminate the 
house-air, the deadly carbon monoxide being particularly 
liable to leak not only through the crevices but actually 
through the heated cast-iron plates, etc., of stoves and 
furnaces. Theoretically, a pound of coal requires 160 
cubic feet of air for its complete combustion, but actually 
from one-half to as much more must be supplied to the 
ordinary heating apparatus to secure perfect oxidation of 
the fuel. 

Practically all the devices for artificial illumination, 
with the exception of the incandescent electric light, give 
off their combustion products, which are much the same 
as those from coal, directly to the air which surrounds 
them, and this contamination is, consequently, a positive 
factor in the vitiation of in-door air. u Every cubic foot 
of coal-gas yields, on combustion, roughly, half its own 
volume, or 0.52 cubic foot, of carbon dioxide, and 1.34 
cubic foot of water vapor/ y beside some little carbon 
monoxide when ordinary burners are used. " Speaking 
generally, it may be said that each cubic foot of gas burnt 
per hour from the ordinary burners vitiates as much air 
as would be rendered impure by the respiration of an in- 
dividual; it, at the same time, will raise the temperature 
of 31,290 cubic feet of air 1° F., and yields 217 calories 
(a kilogramme of water heated 1° C.) or 860 British heat- 
units (a pound of water heated 1° F.). ,M 

The following table 2 will indicate the influence of vari- 
ous lighting agents with respect to the condition of the 
room-air : 



1 Notter and Firth : Treatise on Hygiene, p. 140. 

2 Ibid., p. 141. 



76 A MANUAL OF HYGIENE AND SANITATION. 





•6 

*0 








id 

0) O 


OQ 

^ 


aS ■ 








<° 2 




SI =3 
TO ° 


03 =3 
+3 O 


* 5*2 




a3 O 


3 o 


t*> 0) 


1—3 


•S2 ** 


oi hi 


■S 0^13 




5 O 


m" 


<3*° 


ft 


35 p< 


£ oj oS 




0? 


o 


o 





a 


w 


> 








Cu. ft. 


Cu. ft. 


Cu. ft. 






Tallow candles 


2200 grains 


16 


10.7 


7.3 


8.2 


1400 


12.0 


Sperm candles 


1740 " 


16 


9.6 


6.5 


6.5 


1137 


11.0 


Paraffin oil lamp . 


992 " 


16 


6.2 


4.5 


3.5 


1030 


7.5 


Kerosene oil lamp 


909 " 


16 


5.9 


4.1 


3.3 


1030 


7.0 


Coal-gas, No. 5, batwing 
















burner 


5.5 cu. ft. 


16 


6.5 


2.8 


7.3 


1194 


5.0 


Coal-gas, Argand burner 


4.8 " 


16 


5.8 


2.6 


6.4 


1240 


4.3 


Coal-gas, regeneration (Sie- 
















mens) burner 


3.2 " 


32 


3.6 


1.7 


4.2 


760 


2.8 


Coal-gas (Welsbach incan- 


















3,5 " 


50 


4.1 


1.8 


4.7 


763 


3.0 


Electric incandescent light 


0.3 lb. coal 


16 


0.0 


0.0 


0.0 


37 


0.0 



From this table it will be learned that the incandescent 
light is the most satisfactory from a hygienic point of 
view, and there is no doubt that its very general intro- 
duction of late has done much toward removing a con- 
stant source of vitiation, especially in those rooms which 
require much artificial light, and are at the same time 
difficult to ventilate. It is said that in a large bank in 
London, in which several hundred persons are employed, 
the absences on account of illness have been so far reduced, 
apparently by the introduction of the incandescent electric 
light alone, that the extra labor gained has more than paid 
for the increased cost of lighting. The electric arc light 
is said to form nitric acid; but even so, its effects are not 
so harmful as those of the ordinary candle, lamp, or gas- 
burner. 

Next to the incandescent electric light in importance 
are the Welsbach and Siemens gaslights; but of these the 



THE ATMOSPHERE— AIR. 



77 



latter has not the illam mating power, nor is it so fitted for 
house use as is the former. The Welsbach light makes 
use of the Bunsen flame (in which, by the way, the carbon 
of the gaseous fuel is completely consumed and converted 
into carbonic acid) to render incandescent a non-com- 




CMmney. 



a — Shade Support 



Mantle. 
Mantle Support. 

Chimney Support. 
Gauze Tip. 

Gas Spreader. 

Corrugated Cap. 
liLMantle Carrier. 
^Centre Tube. 

i^Bobesche Support. 

Gallery. 
Bunsen Tube. 

Air Shutter. 



^S^Miustable Check. 
Welsbach light. 

bustible mantle of network, made of the salts of certaiu 
elements which have the property of becomiog intensely 
luminous when sufficiently heated. It gives a very white 
light of great illuminating and considerable actinic power, 
and of practically unvarying intensity. In fact, this 



78 A MANUAL OF HYGIENE AND SANITATION. 

quality of steadiness, in which it surpasses even the in- 
candescent electric light, is by no means the least of its 
hygienic advantages, since such steadiness is an important 
factor in the conservation of the eyesight. 

A comparatively new illuminant, not mentioned in the 
foregoing table, is acetylene gas. This gives a very white 
and powerfully actinic light and, on account of ease of 
production and the small amount needed for ordinary 
lighting, is cheap and does not greatly vitiate the atmos- 
phere. But when mixed with air in proportions of from 
4 to 25 per cent., this gas is highly explosive and, conse- 
quently, is not yet much used for interior lighting. 

Sewer-gas and Soil-air. What is commonly called 
sewer-gas is but a mixture of a number of gases, such as 
carbonic acid, carburetted hydrogen, ammonium and 
hydrogen sulphide, nitrogen, etc., together with a con- 
siderable amount of fetid organic matters, the volatile or 
semi-volatile products of animal and vegetable decompo- 
sition, varying according to the condition of the sewer, 
the kind of matter received therein, the amount of surplus 
water, etc. The air from a closed cesspool may be ex- 
tremely foul and poisonous, so much so that the emana- 
tions have not infrequently brought death to those who 
inhaled them in full concentration; on the other hand, the 
atmosphere of a properly constructed and well-flushed 
sewer may be almost as pure as that above the surface of 
the ground. Bacteria are present in varying numbers, 
with always the possibility of some of them being the germs 
of specific diseases. But fresh sewage is not so likely to 
contaminate the air above it with these microbes as that 
in which decomposition has begun, since Frankland has 
shown that solid or liquid particles are not liable to be 
scattered into the air by any disturbance to which the 



THE ATMOSPHERE— AIR. 79 

sewage is likely to be subjected until gases of decomposition 
are produced. The bursting of bubbles of the gas on the 
surface may then throw the bacteria into the sewer-air. 
It has also been shown that u bacteria can undoubtedly 
grow up the sides or walls of damp, nutrient sewers, and 
if these latter become at all dry, air currents readily de- 
tach and disperse them." 

Another class of impurities that may at times be found 
in the air of dwellings are those coming from the soil and 
soil-air. The soil, in hygiene, refers to all that portion 
of the earth's crust that can in any way affect the health. 
All soils contain more or less air — soft sandstones from 
20 to 40 per cent., loose sands from 40 to 50 per cent., 
and loose soils often many times their actual volume of 
air. 

As the soil is the recipient of most of the solid and 
liquid waste of all animal and vegetable life, and as the 
myriads of saprophytic bacteria that inhabit its upper 
strata are constantly working to convert this dead organic 
matter into simpler compounds suited to the nourishment 
of plant life, the soil air, taking the atmosphere above as 
a standard, will usually be far from pure. 1 It is rich in 
carbonic acid and in organic vapors and gases, while the 
proportion of oxygen seems to be always less than that of 
the air above-ground. Moreover, the carbonic acid in- 
creases and the oxygen decreases the deeper below the 
surface the sample is taken. As much of the carbonic 
acid is evidently derived from the organic pollutions, it 
might be supposed that this gas could be taken as an 
index of the degree of the latter, and so it might if other 

1 Too much importance cannot be attributed to this saprophytic action in the 
upper soil, for it is one of nature's great methods of securing and conserving not 
only the purity of our environment, but the perpetuation of organic life. 



80 A MANUAL OF HYGIENE AND SANITATION. 

conditions, such as permeability of soil, rate of circula- 
tion, etc., were always the same. But they are not, and 
the composition of the soil-air is practically not the same 
at any two places, nor for the same place at different times. 
The underground air is constantly in circulation, even 
to a considerable depth, but there is a hindrance to its 
free movement and diffusibility, and this, together with 
the great variation in the distribution of oxidizable and 
other contaminating matters, causes the variations in its 
composition. The carbonic acid, therefore, cannot be 
taken as an index of the relative purity. 

The forces that maintain the circulation of the ground- 
air are the wind, the daily change of surface temperature, 
the fall of rain, and, especially in winter, the local and 
artificial conditions of civilization. A very slight wind 
will drive the air through the soil for long distances, the 
rise and fall of the ground-water has its obvious effect, 
and the movement due to even slight changes of tempera- 
ture is likely to be quite extensive and positive. 

Owing to evaporation from the ground-water, the soil- 
air is always quite humid, and, according to some writers, 
may also be laden with bacteria and other light substances 
lifted up by the ascensional powers of evaporation. 

As sewage, house-w r astes and dirt of all kinds are par- 
ticularly liable to contaminate the soil about any used 
dwelling, the air of that soil will be more than likely to 
be very impure, and care must be taken that it is not 
drawn into the house. This is especially apt to happen 
in cold weather when the house fires are lighted and the 
in-door air is thus made warmer than that without, the 
tendency then being for the soil-air to pass, if possible, 
through the cellar walls and floors. These should be 
made as nearly air-tight as possible, and special attention 



THE ATMOSPHERE— AIR. 81 

should be given to the space underneath and about 
the furnaces or basement heating apparatus. As an in- 
stance of the importance of these precautious, Dr. Hime 1 
gives an account of the fatal poisoning of four persons. 
Sufficient illuminating (coal) gas was drawn through 
fifteen feet of soil and the foundation walls of the dwell- 
ing from a broken pipe, although there were only eight 
or ten inches of tramped earth above the latter and the 
only aspirating force was the difference of temperature 
within and without the house. A number of serious ex- 
plosions have occurred, due to a similar leakage of gas 
from street-mains through basement walls or into drains 
and sewers, since the mixture of illuminating-gas with 
air forms a most powerful and dangerous explosive. 

There is no direct evidence that the emanations from 
bone-yards, soap-factories, garbage-incinerators, etc., are 
really harmful to health, but they may be very decided 
nuisances to those living near by, and all such places 
should be strictly controlled by the proper sanitary 
authorities. 

The atmosphere of mines and other excavations is sub- 
ject to contamination by the excess of carbonic acid in the 
soil-air, by gases from fissures in the rock and from blast- 
ing agents, and by the products of respiration from men 
and animals working in the mines, etc. The air in the 
holds of ships is also likely to be foul, owing to the diffi- 
culty of changing it sufficiently often, and frequently also 
to the insanitary character of the cargoes. In such situa- 
tions proper ventilation should be secured by all means 
available, and special care taken that the impure air does 
not affect the laborers in the one case and the passengers 
and crew in the other. 

1 Stevenson and Murphy : Treatise on Hygiene, vol. L, p. 949. 

6 



82 A MANUAL OF HYGIENE AND SANITATION 

Diseases Caused by Impure Air. As a rule, the 
human system has the power of accommodating itself, 
through habit, to withstand influences which, in one 
unaccustomed to them, would soon produce serious re- 
sults. But in spite of this, if the body be exposed for 
any considerable length of time to conditions of impurity 
or deterioration in its supply of air, water or food, such 
conditions will always tend to undermine health and in- 
crease the susceptibility to disease, even though they 
cause no more serious results. " Statistical inquiries 
on mortality prove beyond a doubt that of the causes of 
death which are usually in action, impurity of the air is 
most important. No one who has paid any attention to 
the condition of health, and the recovery from disease of 
those persons who fall under his observation, can doubt 
that impurity of the air marvellously affects the first, and 
influences, and sometimes even regulates, the second. 
The air may affect health by variations in the 
amount or conditions of its normal constituents, by dif- 
ferences in physical properties, or by the presence of 
impurities. While the immense effect of impure air can- 
not be for a moment doubted, it is not always easy to 
assign to each impurity its definite action. The evidences 
of injury to health from impure air are found in a larger 
proportion of ill health — I. e., of days lost from sickness 
in the year — than under other circumstances; an increase 
in the severity of many diseases, which, though not 
caused, are influenced by impure air, and a higher rate 
of mortality, especially among children, whose delicate 
frames always give us the best test of food and air." 1 

The definitely marked diseases caused by the solid im- 



j p 



tevenson and Murphy, vol. i., pp. 121 and 122. 



THE ATMOSPHERE— AIR. 83 

purities in the atmosphere are almost all such as affect 
the respiratory passages and organs, with the possible 
exception of those engendered by specific bacteria and 
other minute organisms. Much, therefore, depends upon 
the physical character of the dust and solid impurities. 
Soft particles and those with edges smooth and rounded, 
like soot and coal-dust, may apparently do nothing more 
than coat or clog up the air-vesicles and finer bronchial 
tubes, and in this way diminish the area of lung tissue 
exposed to the inspired air, although it is questionable 
whether any foreign matter in the lungs does not cause 
more or less actual irritation. With most of us, how- 
ever, such impurities are of little account if pains be 
taken to develop the full respiratory capacity of the 
chest; but where the air is heavily charged with such 
dust it has a real effect upon health and duration of life. 
In 1862 Sir John Simon stated that with one exception 
" the 300,000 (coal) miners of England and Wales break 
down as a class prematurely from bronchitis and pneu- 
monia, caused by the atmosphere in which they live. 
The exception is important. The colliers of Durham and 
Northumberland, where the mines are well ventilated, do 
not appear to suffer from an excess of pulmonary dis- 
eases, or do so in a slight degree only." Happily, since 
this was written satisfactory ventilation systems have 
been placed in most of the collieries of England, and 
the condition of the laborers correspondingly improved; 
but coal miners are still, as a class, particularly liable to 
bronchitis, pneumonia, asthma, emphysema and fibrosis 
(fibroid phthisis), though they seem to be but slightly sub- 
ject to primary tuberculosis of the lungs or other organs. 
On the other hand, if the particles of dust in the air 
are hard, angular, and sharp, the lung tissues are readily 



84 A MANUAL OF HYGIENE AND SANITATION. 



lacerated, inflammatory processes are quickly set up, and 
the opportunity for the inoculation of tubercle bacilli and 
other disease-germs is very great. The mortality from 
tubercular phthisis among metal miners, needle-cutters, 
steel-grinders and tool-grinders, cotton-spinners, etc., is 
remarkable, and they are also especially subject to asthma 
and emphysema. Among Cornish tin miners, 68 per cent, 
of all sick are consumptive; of needle-makers, over 60 
per cent.; of flint cutters, glass-cutters, and polishers, and 
of grindstone makers, from 80 to 90 per cent., etc. It 
is said that a mixture of mineral and metallic dust seems 
to be more harmful than metallic dust alone, perhaps be- 
cause of the increased clogging of the air- vesicles by the 
mineral matter. 

Likewise, with other occupations where there is much 
irritative dust floating in the air, the effect upon the 
health of the worker is marked, and we will find lung 
troubles prevalent and many sick and dying from phthisis, 
as, for instance, among cotton-spinners, flax-dressers, 
hemp-dressers, pottery-makers, etc. Bad ventilation, 
accumulations of noxious gases, improper habits, insuffi- 
cient disinfection of sputa, and often the excessive 
humidity of the air necessary in some of these pursuits, 
have doubtless something to do with the high sick-rates 
and death-rates; but withal, the marked effect of the solid 
atmospheric impurities cannot be denied. 

Again, workers in poisonous metals, compounds or gases, 
such as paintmakers and painters, type-setters, gilders 
(using mercury), brass-founders, coppersmiths, etc., are 
subject to the respective poisons and the symptoms pro- 
duced by them, with a correspondingly increased mortality. 

Among the diseases that may be caused by the inhala- 
tion or swallowing of specific micro-organisms floating in 



THE ATMOSPHERE— AIR. 85 

the atmosphere are erysipelas, measles, scarlet fever, diph- 
theria, whooping-cough, infectious pneumonia, phthisis and 
other forms of tuberculosis, and very probably epidemic 
influenza; and, although the germs of cholera and typhoid 
fever are usually carried by the drinking-water or food, 
they doubtless do sometimes find their way into the system 
from a contaminated atmosphere. 1 Malaria also is now 
practically proven to be due to a minute organism, which, 
though usually introduced into the human body in other 
ways, may possibly be present in the air of malarial dis- 
tricts, and may be carried long distances thence by the 
winds. 

Lastly, the spores of certain fungi, which have been 
found in the air of hospitals and elsewhere, are known to 
cause skin diseases, such as the tineas and favus in men; 
and it is almost as certain that the irritating or poisonous 
pollen of certain grasses and other plants have much to 
do with the causation or aggravation of such maladies as 
hay-fever and rose-fever. 

From what has already been said it will be surmised 
that it is scarcely possible, at present, to specify the exact 
effect upon the health of each of the impurities given to the 
air by the human body, and that the symptoms observed 
to be due to air thus vitiated are very probably an evi- 
dence and result of the combined action of these factors 
rather than of any one of them singly. However, the 
writer feels that the oppression so commonly experienced 
is often fairly attributable to the increase in the tempera- 
ture and humidity; that the headache, disturbed nutrition, 

1 The report of the commission appointed to inquire into the prevalence and 
causes' of typhoid fever in the late Spanish-American war shows that in some 
cases infection was prohahly due to the dust in the atmosphere, which had been 
raised by many passing feet from the roads over which leaking sewage wagons 
had been hauled. 



86 A MANUAL OF HYGIENE AND SANITATION. 

and febrile condition, lasting for hours and sometimes 
days after exposure to air thus vitiated, are either effects 
of the organic matter acting as a poisonous waste when 
taken back again into the system, or results of the sup- 
pression of cutaneous excretion dependent upon the high 
content of moisture in the air; and that the respiratory 
carbonic acid by itself can but rarely have much influence 
upon comfort or health. 

If the respiratory and cutaneous vitiation be sufficient 
to produce any acute effects, the immediate symptoms 
will be a discomfort and sense of oppression, followed by 
headache and not rarely nausea and a rather decided 
rise of temperature, all of which may last for some time, 
even after the individual goes into perfectly pure air. 
Those who habitually live in such an atmosphere are 
almost uniformly languid, pallid, and anaemic, subject to 
headaches, nausea and loss of appetite, and often to skin 
eruptions and disorders, and are undoubtedly markedly 
predisposed to phthisis, pneumonia, bronchitis, scrofula, 
rhachitis, etc. Moreover, such an atmosphere apparently 
favors the rapid spread, increases the severity of and 
retards the convalescence from such diseases as diph- 
theria, scarlet fever, measles, typhus, smallpox, etc. 
This may be due either to the accumulation or to the 
actual multiplication by growth of the disease germs in 
the foul air, or to the latter causing a decrease of bodily 
resistance and an increase in predisposition to such mala- 
dies. 

When the proportion of impurities is very great, the 
results may be very serious and even fatal, as in the well- 
known cases of the "Black Hole of Calcutta;" of the 
prison in which 300 captives of war were crowded after 
the battle of Austerlitz (260 dying very soon after being 



THE ATMOSPHERE— AIR. 87 

placed therein), and of the steamer " Londonderry," in 
which, of 200 steerage passengers who were temporarily 
crowded into a cabin (18 x 11 x 7 feet) during a storm of 
only a few hours' duration, seventy-two were dead and 
others dying when the cabin was opened. 

As regards the influence of combustion-products on 
health, it will suffice to detail the symptoms produced by 
the inhalation of the various gases. It will be difficult 
to show that these gases, together with the coincident 
soot, have any general effect upon health when escaping 
into the out-door atmosphere, even when produced in such 
enormous quantities in cities as has been already indi- 
cated. It is possible that the sulphur dioxide and other 
sulphur gases might favor or aggravate attacks of bron- 
chitis or asthma in those living in the vicinity of gas- 
works, chemical factories, etc., but too little comes from 
ordinary chimneys to do much, if any, harm. 

In-doors the case is different, for the gases from lights 
and fires become more and more concentrated as the ven- 
tilation is insufficient. The possible effects of varying 
percentages of carbonic acid have been noted. We have 
no evidence of cases of chronic poisoning by this gas, 
although, as Parkes says: " The presence of a very large 
amount of C0 2 in the air may lessen its elimination from 
the lungs, and thus retain the gas in the blood, and thus 
in time possibly produce serious alterations in nutrition." 

In cases of acute poisoning by this gas — I. e., where it 
is in great excess in the atmosphere — there is an almost 
immediate loss of muscular power and the person may 
consequently be unable to remove himself from the place 
of danger, while others who go to help him may also 
succumb and more than one be asphyxiated. Accord- 
ingly, volunteer rescuers should always remember to act 



88 A MANUAL OF HYGIENE AND SANITATION. 



with coolness and great rapidity, and to provide means 
for the prompt removal not only of the ones they would 
save, but of themselves. Fortunately, when one who has 
been overcome by carbonic acid is brought into an atmos- 
phere of pure air before life is extinct and is aided by 
artificial respiration, he usually recovers rapidly and com- 
pletely because of the rapid escape of the excess of the 
gas from the blood and its replacement by the necessary 
oxygen. Death from carbon dioxide poisoning is prob- 
ably mainly due to asphyxia, partly from lack of oxygen 
and partly from paralysis of the respiratory muscles, 
though the latter, as well as the general motor palsy, 
would seem to indicate that the gas itself had a positive 
physiological effect upon the nerve centres. 

Cases of poisoning by carbon monoxide are much more 
serious. Recovery from its effects is slow and uncertain, 
because this gas unites with the haemoglobin of the red 
blood-corpuscles, paralyzing them, as it were, and ren_ 
dering them unable longer to act as oxygen carriers to the 
tissues; while the union of carbon dioxide with the blood 
is always an unstable one and readily broken as soon as an 
interchange with a normal atmosphere is available. Less 
than one-half per cent, of carbon monoxide in the air has 
caused symptoms of poisoning, and more than two or 
three per cent, is fatal to animals. " It appears that 
the gas, volume for volume, completely replaces the oxy- 
gen in the blood, and cannot again be displaced by oxygen, 
so that the person dies asphyxiated; but Pokrowsky has 
shown that it may be gradually converted into carbonic 
dioxide and be got rid of." 

The symptoms of carbonic oxide (monoxide) poisoning 
are feebleness, oppressed breathing, trembling, and in- 
ability to swallow; then " loss of consciousness, drstnio- 



THE ATMOSPHERE— AIR. 89 

tion of reflex action, and finally paralysis of the heart/ ' 
" Hirt says that at high temperatures (25° to 32° C. = 
77° to 90° F.) it produces convulsions, but not at low 
temperatures (8° to 12° C. = 46° to 54° F.)." The blood 
and muscles are made a brilliant red by this gas, darkened 
by carbon dioxide. Claude Bernard says that a mixture of 
these two gases is more destructive than either separately, 
probably because the excess of the acid gas interferes with 
the conversion of the monoxide to the dioxide in the 
blood, as was shown by Pokrowsky. 

Illuminating or coal-gas — composed of hydrogen, light 
and heavy carburetted hydrogens, a little nitrogen, and 
carbonic acid, and from 5 to 7 per cent., or even more, 
of the carbon monoxide — rapidly causes, when inhaled, 
giddiness, headache, nausea and vomiting (?), confusion 
of intellect, loss of consciousness, general weakness and 
depression, partial paralysis, convulsions, and the usual 
symptoms of asphyxia. Mixed in large proportions with 
the air, death may ensue comparatively quickly, probably 
because of the large content of carbon monoxide. It is 
well to remember that the so-called water-gas, now so 
extensively manufactured for fuel purposes and also for 
diluting coal-gas, contains a much larger percentage of 
carbon monoxide (sometimes from 30 to 40 per cent.) 
than the latter, and that the symptoms resulting from the 
inhalation of a mixture of the two will be in all likelihood 
more marked, more rapid, and more deadly than with the 
undiluted coal-gas. 

" The effects of constantly inhaling the products of gas 
combustion may be seen in the case of workmen whose 
shops are dark and who are compelled to burn gas dur- 
ing a large part of the day; the pallor, or even anaemia 
and general want of tone, which such men show, are 



90 A MANUAL OF HYGIENE AND SANITATION. 



owing to the constant inhalation of an atmosphere so im- 



yy 



pure 

Sulphurous acid gas (S0 2 ) and sulphuretted hydrogen 
(H 2 S) are each fatal to life, the latter when in a compara- 
tively concentrated state; but they are offensive and irri- 
tating to the senses and thus give warning of their pres- 
ence, so that there is less danger of their causing serious 
results. Men can accustom themselves to much larger 
proportions of sulphuretted hydrogen in the atmosphere 
than can animals, but continued exposure to it is liable 
to give rise to vertigo, headaches, slow and weak pulse, 
sweatings and loss of strength. 

When sewer-gas or soil-air escape into the outer air 
they are usually soon diluted beyond any power for harm; 
but if either gains access to closed rooms or unventilated 
dwellings, its effects upon the inmates is depressing and 
decidedly bad. In either case, concentration of the im- 
purities may cause acute symptoms, such as vomiting, 
purging, severe headache and prostration, and either 
soil-air or sewer-gas may at any time carry the germs of 
infectious diseases. Their influence, however, is usually 
insidious, owing to dilution with the house-air, and the 
more common symptoms will probably be pallor, languor, 
frequent headaches, loss of appetite, diarrhoea, impaired 
health, and often chronic anaemia. Children especially 
suffer in nutrition, and with them febrile attacks may be 
frequent ; but with all, the power of resisting such dis- 
eases as typhoid fever, diphtheria, etc., is lessened and 
the susceptibility to them is increased, the sickness more 
severe, and the convalescence more prolonged. Indeed, 
sewer-gas and soil-air probably aggravate all diseases. 

In this connection Alessi has shown that when small 
animals, such as rabbits, rats and guinea-pigs, have been 



THE ATMOSPHERE— AIR. 



91 



exposed to sewer-air for some days, by far the larger 
majority when inoculated with only a small quantity of 
a slightly virulent typhoid culture contract the disease 
and die, while almost none of those treated similarly in 
every way excepting by the exposure to sewer-air suc- 
cumb. He also showed that the inoculations were more 
deadly when the previous exposure to the noxious gas 
had been less than two weeks than when it exceeded that 
period, indicating that animals, as well as persons accus- 
tomed to such contamination, are not apt to manifest the 
symptoms due to it so rapidly or so seriously as are those 
who experience it for the first time — a fact well known to 
all observers. It is only fair to say that these experi- 
ments of Alessi have apparently been controverted by 
other observers; but, whichever may be correct, the truth 
of the following quotation doubtless still holds good : 

" There is undoubtedly a poisonous agency at work 
when sewer-gas is inhaled, which, though it may not 
directly act, yet so prepares the soil that the system is 
unable to resist the invading organism when it comes." 1 



1 Notter and Firth, p. 159. 



CHAPTEE IV. 



VENTILATION AND HEATING. 



As we are not usually able to destroy the impurities of 
the atmosphere within our dwellings as fast as the former 
are produced, we have recourse to ventilation as a means 
for their dilution and prompt removal. We must not 
think, however, that we do all that is necessary if we 
only renew the in-door air, for unless the source and 
supply from which we take that which is to replace or 
dilute the vitiated air be pure and clean, any system of 
ventilation which we may adopt will be of little value. 

External ventilation of our buildings, streets and cities 
is of importance, then, as welLas that which relates only 
to the interior of our dwellings, workshops and places of 
assembly. Numerous investigations and statistics, both 
here and abroad, show that " the health of a town largely 
depends upon the width of the streets, the general height 
of the buildings, and the amount of yard space at the rear 
of each which separates it from its opposite neighbor." 
It is also difficult to overestimate the value of wide streets, 
numerous diagonal ones and frequent parks or open 
spaces, especially in the more thickly inhabited portions 
of a city. In this connection we may refer with advan- 
tage to some work of Dr. H. S. Anders, of Philadelphia, 
in which he shows that u the number of deaths from 
phthisis on a very wide street is proportionately small 
compared with those on almost any one narrow street," 
and " that there is plainly and generally a high mortality- 



VENTILATION AND HEATING. 



93 



rate from consumption associated with street narrowness 
in not a small part of Philadelphia, and that the relation 
between a high mortality and narrow streets is a positive 
and vital one." His statistics, covering a period of 
fifteen years, show that in one city ward, certainly 
favored as to location, the ratio of deaths from phthisis 
per square or block on streets over to those on streets 
under forty feet in width was approximately as 3 is to 5. 

As regards internal ventilation, it will be well to deter- 
mine at the outset the meaning and limitations of the 
term. Parkes says : u It will be desirable to restrict the 
term ventilation to the removal or dilution, by a supply 
of pure air, of the pulmonary and cutaneous exhalations 
of men, and of the products of combustion of lights in 
ordinary dwellings, to which must be added, in hospitals, 
the additional effluvia which proceed from the persons 
and discharges of the sick. All other causes of impurity 
of air ought to be excluded by cleanliness, proper removal 
of solid or liquid excreta, and attention to the conditions 
surrounding dwellings." AYith the function of ventila- 
tion thus limited, it will not be necessary to make provi- 
sion for such an abundant supply of pure air as might 
otherwise seem advisable. It is evident, also, that the 
purity of in-door air must almost always be relative and 
not absolute, especially in a climate like ours, which for 
a considerable portion of the year necessitates the warm- 
ing of the air and some consequent economy in its use. 

It seems strange that attention has not been given 
to the possibility of purifying a vitiated atmosphere by 
means of fire rather than by the removal or dilution of 
the impurities, especially as we so often employ heat as 
an agent to destroy or alter the harmful qualities of other 
substances intimately concerned with our welfare. The 



94 ^ MANUAL OF HYGIENE AND SANITATION. 

objection that many would offer at first thought to such a 
plan is that the fire would rob the air of all or most of its 
oxygen, but a little calculation and consideration will show 
that this is by no means a necessary result, and that a 
proper apparatus might actually require but comparatively 
little of this gas and give off but little carbonic acid as a 
combustion product to the atmosphere. So far as the 
writer knows, but one device on the market has this func- 
tion professedly embodied in it, and it apparently does 
what is claimed for it in this respect. The possibilities 
of the suggestion invite further investigation. 

To discover the quantity of air desirable and consistent 
with the requirements of good ventilation and the non- 
interference with health two factors must be determined: 
(a) The extent to which the air of a room is contaminated 
in a given time by the impurities it receives, and (6) the 
limit of permissible impurity beyond which there will be a 
possible risk or detriment to health. In accordance with 
the above mentioned limitations of Parkes, the contami- 
nating substances will usually be comparatively few in 
number, but the same factors are to be sought in the case 
of any detrimental substances in the atmosphere at any 
time, provided their source or cause cannot be directly 
removed. 

Although it is extremely difficult to determine quanti- 
tatively the organic matter given off by human exhalation 
in any given time, the carbonic acid, as has already been 
stated, is usually exhaled in a reasonably constant ratio 
with it, and can, therefore, be used as an index of the 
amount of it contaminating the air. Taking Pettenkoffer's 
figures, which have been substantially confirmed by other 
investigators, viz., 0.6 of a cubic foot of carbonic acid per 
hour per head for a mixed assemblage at rest, 0.7 of a 



VENTILATION AND HEATING. 



95 



cubic foot for adult males, and increasing amounts accord- 
ing to the physical work done, we have the first factor (a) 
of our problem determined for all cases where the prod- 
ucts of respiration are the only contaminants. 

In establishing the limit of permissible impurity — the 
second factor (6) — it will naturally be advisable to require 
that the supply of air from without shall be sufficient not 
only to be thoroughly consistent with health, but that 
there may be no perception of impurity by the senses, the 
air of the room remaining apparently as fresh and pure as 
that out-of-doors. To this end Dr. de Chaumont made a 
large number of observations (over 450), and found that 
as long as the carbonic acid due solely to respiratory im- 
purity did not exceed 0.02 per cent, the in-door air did 
not differ sensibly from that without, but that when the 
respiratory C0 2 reached 0.04 per cent, the air was rather 
" close " and the organic matter was becoming perceptible 
to the sense of smell. Subsequent investigations have 
shown that as long as the respiratory C0 2 does not ex- 
ceed 0.02 per cent, it has no perceptible effect upon the 
health; consequently, we may take this amount of car- 
bonic acid, over and above the amount normally present at 
the time in the outer atmosphere, as our limit of permissible 
respiratory impurity in ordinary inhabited apartments. 

Having now the two factors of our problem, and pro- 
vided there are no other sources of contamination, it be- 
comes a simple matter of proportion to determine the 
quantity of fresh air to be supplied to each individual. 
The equivalent of 0.02 per cent, is 0.0002 of a cubic foot 
of carbon dioxide in each cubic foot of air. In a mixed 
assembly at rest each person exhales 0.6 of a cubic foot 
of carbon dioxide per hour. Consequently, to properly 
dilute this respiratory C0 2 and its coincident organic 



96 & MANUAL OF HYGIENE AND SANITATION. 

n (\ 
effluvia, each person will need — - — or 3000 cubic feet 
F 0.0002 

of fresh air per hour. If the individuals are all adult 
males, or if they are working, there must be a corre- 
sponding increase in the air supplied, running up to 
6000 or even 9000 cubic feet or more per head in certain 
laborious occupations. This is the theoretical amount 
of pure air necessary for good ventilation, but in prac- 
tice we find that we can get along with safety and 
comfort with somewhat less, because some of the bodily 
impurities are almost at once carried away and out 
of the room by the draughts through the exits, or 
through the cracks and crevices in the walls and ceiling 
which act as exits, and the incoming air does not, there- 
fore, have to mix with and dilute that portion of the im- 
purities that is so immediately removed. In other words, 
if ten per cent, of the vitiation is thus directly taken away, 
ten per cent, less of pure air is needed to dilute the remain- 
ing contaminants to the limit of permissible impurity; 
but as the quantity and the consequent velocity of the 
incoming or of the outgoing air diminishes, less and less 
of the impurities are thus directly removed, and expe- 
rience teaches that almost the entire theoretical supply 
of fresh air is actually needed in practice to secure satis- 
factory results. 

Provision must also be made for sufficiently diluting the 
impurities from other sources of vitiation whenever they 
are present. Although combustion products are not usu- 
ally as dangerous as impurities from the human body, and 
are generally massed near the top of the room on account 
of their high temperature, we should provide at least 1800 
cubic feet of air for each cubic foot of gas burned, and 
ten times as much for each pound of oil consumed. 



VENTILATION AND HEATING. 



97 



In sick-rooms and hospitals an exception mast also be 
taken to the equation in which 0.02 per cent, of carbonic 
acid is taken as the permissible respiratory impurity, for 
it is found that the organic matter exhaled from the sick 
is much more offeusive than that from the healthv, and is 

ml 7 

noticeable to the senses when the respiratory C0 2 is even 
below 0.02 per cent. So, at least one-fourth or more of clean 
air must be added to the quantity necessary for the healthy, 
and a good rule is to give the sick as much as possible, 
provided it be properly warmed and distributed. 

The use of the following formula will often be of ad- 
vantage in solving problems relating to ventilation, viz.: 

_ = d, where e represents the amount of carbonic acid ex- 
r 

haled in the given time, r the respiratory C0 2 in parts per 
cubic foot, and d the delivery or volume of fresh air in 
cubic feet. 1 Example: What will be the respiratory im- 
purity in the air of a room of 3000 cubic feet capacity 
which has been occupied by three men for two hours, 
supposing that there has been an ingress of 9000 cubic 
feet of fresh air in that time? Here e = 0.7 X3X2 = 



= 12,000 u 



4.2, and d = 3000 + 9000 = 12,000. — 

r 

■*' 2 =r = 0.00035 = 0.035 per cent. C0 2 . 
12,000 F 2 

Before considering the means by which a sufficient 
quantity of pure air may be supplied to buildings and 
apartments, it will be well to note the following restric- 
tions as to the size and height of the rooms. If a room 
be too small, the air therein will have to be changed often, 

1 By allowing e to represent the total contamination per hour, and r to repre- 
sent the limit of permissible impurity in any given case, this formula can be used 
for almost any other ventilation problem, whatever may be the contaminants or 
source of impurity. 

7 



98 A MANUAL OF HYGIENE AND SANITATION. 

the velocity at the inlets will be increased, uncomfortable 
draughts will be created, and the air will not diffuse itself 
so thoroughly throughout the room. Experience shows 
that even when the air is properly warmed it cannot be 
changed much oftener than three times an hour without 
discomfort to the occupants of the room, unless the ven- 
tilating apparatus be very perfect in its workings and, 
therefore, expensive. Consequently, as we take 3000 
cubic feet of fresh air to be the average amount required 
per person per hour, the cubic space per individual should 
be at least 1000 cubic feet, with a corresponding increase 
where the occupants are all adult males, are all at work, 
or are in hospitals. 

Again, it must be remembered that the difficulty of 
securing equable heating and ventilation increases with 
the height of the room above a certain limit, and that 
with the sick especially a certain amount of floor-space is 
necessary, both for the separation of patients and conve- 
nience of attendance. Ten or twelve feet will usually be 
found to be the safe limit of height for all apartments 
intended for continuous rather than temporary occupation, 
and, consequently, there should be a minimum allowance 
of from 85 to 100 or more square feet of floor-space per 
head, and an increase even upon this in workshops, hos- 
pitals, etc. However, there is no objection to high ceil- 
ings if you are not limited as to floor-space, pure air sup- 
ply, and heat; and they may even be advisable in rooms 
where many lights are to be burned. Again, these re- 
strictions regarding cubic and floor-space do not neces- 
sarily apply to such buildings as churches, theatres, etc., 
which are occupied for only a comparatively limited 
time, which can be thoroughly flushed out after use, and 
in which it is evidently impracticable to alio? to each 



VENTILATION AND HEATING. 



99 



person the above floor-area. Yet pains must be taken in 
such assemblies to keep the atmosphere pure by whatever 
means are necessary; while for school-rooms and the like 
there must be extreme care that the pupils are not over- 
crowded, and that they have a full supply of properly 
warmed air. 

Any correct system of ventilation, in addition to the 
above considerations, must take into account the source 
of the air supplied, the distribution, and the heating or 
cooling of the air when necessary. 

The air supplied to any house should be taken from 
well above the level of the ground, where it is free from 
contamination and is constantly changing, and not from 
cellars or closed areas, where the atmosphere is stagnant 
and full of impurities. The conduits leading to the 
heating or ventilating apparatus should also be so 
arranged that they may be frequently and readily cleaned. 
It is well to have them covered with gratings to prevent 
objects being thrust into them, and in some cases it may 
even be advisable to filter the air through coarse cloth or 
fine wire-gauze to free it from dust and other impurities. 
In the mechanical system of ventilation adopted in the 
chemical laboratory of University College, Dundee, the 
air is filtered by being passed through jute cloth (light 
Hessian) stretched on frames seventeen feet long by four 
feet wide. In this case the presence of the screen actu- 
ally increased the delivery of the air by nearly 10 per 
cent., probably by preventing eddies. The screens col- 
lected two and one-half pounds of dirt in seven weeks. 
They last about a year, and the cost is about 2d (four 
cents) a yard. 1 In the clinical amphitheatre of the 



LofC. x 



Stevenson and Murphy, vol. i., p. 51. 



100 A MANUAL OF HYGIENE AND SANITATION. 




Medico-Chirurgical College and Hospital of Philadelphia 
a double thickness of fine wire gauze is used to filter the 
air after a preliminary spraying with water, the result 
being entirely satisfactory. 

The air may be kept in motion and efficient ventilation 
secured (1) by those forces continually acting in nature, 
producing natural ventilation, and (2) by these in com- 
bination with other forces set in action by man, giving 
artificial ventilation. The three main forces of natural 
ventilation are diffusion, the winds, and the motion caused 
by the difference in weight of volumes of air of different 
temperatures. 

Diffusion is constantly taking place between all the 
gaseous constituents and impurities of the air, and even 
goes on through brick and stone walls, but is insufficient 
in itself to keep the air pure, though it does much to 
further this. Moreover, as suspended matters are solid, 
not gaseous, they are not changed or removed by it. 

However, the action of this force should not be ignored 
in our calculations as being insignificant, for it is not only 
continuous, but it affects the whole volume of the atmos- 
phere in maintaining its uniformity of composition. 
" Roscoe found that when he evolved carbon dioxide in a 
room the amount had decreased one-half from that cause 
(diffusion) in ninety minutes." l The rate of diffusion is 
inversely as the square roots of the densities of the gases 
concerned. 

Winds are powerful agents for ventilation, and a slight 
breeze passing through a room changes the air therein 
many times in the course of an hour, and carries out by 
its force many of the solid impurities not affected by dif- 

> Notter and Firth, p. 194. 



VENTILATION AND HEATING. 



101 



fusion. Wind will pass through walls of wood, brick 
or stone, although its progress is markedly arrested by 
much moisture in the walls and by paper or plaster. 
The average rate of movement of the wind is consider- 
able, but the difficulties in the way of utilizing it in ven- 
tilation is the uncertainty of its direction and velocity, 



Fig. 13. 




Cowl or ventilator for aspiration. 

the difficulty of regulating it, and the fact that it may 
fail us at a time when we need its action most. In winter 
it usually has to be excluded directly from our houses, 
because a velocity of five or six feet per second is not to 
be borne unless the air be previously warmed. AYe may, 
however, take advantage of the fact that a small current 



102 A MANUAL OF HYGIENE AND SANITATION. 



with a high velocity will set in motion a large volume of 
air, and that wind blowing across the top of a tube will 
cause an upward movement of air in the tube. This is 
one reason why there is almost always a draught up an 
unused chimney and why it acts as a good ventilating 
outlet. 

To utilize these perflating and aspirating powers of the 
wind, and to prevent back draughts down chimneys and 
ventilating pipes, we make use of so-called ventilators or 
cowls, either movable or fixed. We can so arrange these 
that the force of the wind either drives air into the house 
(perflation), or draws air out of it (aspiration). Very 
good systems employing these have been put in operation, 
the air being warmed, if necessary, by passing it over 
stoves, steam coils, etc., and they are especially useful 
where the inner air is colder than that externally, and 
where artificial methods of ventilation dependent upon 
heat cannot be employed, as, in the holds of ships, deep 
basements, etc. 

The most important agent in natural ventilation is, 
however, the movement produced by variations in the 
specific gravity of air. Though the wind might be in- 
cluded under this head, being produced by the same 
force, the air acts independently of the wind, espe- 
cially in closed buildings. As the air expands when 
heated, it becomes lighter, volume for volume, and rises 
because the colder, heavier air pushes in beneath to 
occupy the space. But in all inhabited apartments a 
warming of the atmosphere is continually taking place, 
not only by the lights and heating apparatus, but also 
by the bodies of the occupants. The movement is, 
therefore, a continual though not necessarily an equa- 
ble one, varying as it does with the temperature of 



VENTILATION AND HEATING. 



103 



the out-door air and the Dumber and intensity of the 
heating agents within. There being such a warming 
and movement of the air, it follows that, unless a room 
be perfectly air-tight, some of the apertures Avill act as 
inlets and others as outlets, and the quantity flowing 
out of the room will be practically equivalent to that 
flowing into it. Therefore, though this force may not be 
as powerful or efficient as strong winds at certain times, 
yet being more constant, more readily determined, calcu- 
lated and more controllable, it is the one most to be con- 
sidered in arranging a system of ventilation. 

To determine the velocity of the influx or outgo of air, 
we make use of the law that a fluid passes through an 
opening in a partition between two volumes of the fluid 
with the velocity which a body would acquire in falling 
through a height equal to the difference in level of the 
fluid on the two sides of the partition. In the case of a 
current of air we substitute for the difference of level the 
difference in pressure on the two sides of the partition or 
opening, and this is expressed by the difference in tem- 
perature multiplied by the difference in height of the 
openings of entrance and exit, and divided by 491, 



4 9 1 



representing the expansion of the atmosphere in volume 
and the lessening of density for each degree (Fahrenheit) 
of rise in temperature. The velocity will, therefore, equal 



#^ 



in temp.) X (diff. in height). 



491 



Example: What is the velocity of the current in a chim- 
ney 40 feet high, the out-door temperature being 20° F. 

and in-doors 70° F.? Answer : V= 8 -J- 
2 -(-, or about sixteen feet per second. 



/5 X 40 
491 



8 X 



104 A MANUAL OF HYGIENE AND SANITATION. 

In actual practice use is made of a table derived from 
this formula, or else the velocity is determined directly 
by means of the anemometer. Allowance must be made 
for the frictiou of the air against the sides of the ducts and 
against itself, amounting to from one-fourth to one-half 
of the theoretical delivery, according to the length, size, 
straightness, etc., of the inlets and outlets. The friction 
will be inversely as the diameter of the openings and 



Fro. 14. 



i s 




Anemometer, used fur measuring the velocity of air-currents directly, a, slide 
for releasing or stopping the dial hands ; e, support for attaching the instrument 
to a staff or cane. 

directly as the length of the tubes; the shape of the 
openings also affect it, and right angles diminish the 
current one-half. Accumulations of dust and dirt greatly 
lessen the velocity. 

The velocity multiplied by the total area of the inlets 
or outlets, with a proper allowance for friction, will give 
the quantity of air passing through the rooms or series of 
rooms in any given time. 



VENTILATION AND HEATING. 105 

One of the most difficult problems in ventilation is to 
secure a uniform distribution of pure air through the 
rooms, and to remove the impure air as fast as the pure 
is supplied, thus preventing its mixing with the latter. 
Certain circumstances always make the question compli- 
cated : the size and number of inlets and outlets, the rate 
and direction of motion, and the forces acting to produce 
it must always be subject to constant change, and must 
thus constantly alter the result. In fact, it is practically 
impossible to devise a plan that will satisfy all conditions 
at all times, and the best that can be done will be to select 
that one which will give the greatest efficiency and most 
satisfactory results under all ordinary circumstances. 

The force of diffusion will always act as long as there 
is any communication between the exterior and interior, 
and no special attention need be given to it. For reasons 
already given, we cannot use the wind continually, but 
we should employ it whenever possible by opening doors 
and windows, on account of its great power for sweeping 
out solid impurities and thoroughly changing the air. In 
cold weather, currents from windows, etc., should be 
directed toward the ceiling, so that they may be diffused 
and partially warmed before reaching the inmates of the 
room. Numerous devices have been suggested for intro- 
ducing unwarmed out- door air without discomfort, or for 
diffusing it through the room : among these may be men- 
tioned perforated bricks, or doubled-paned windows, 
valves, screws, etc. A cheap and satisfactory temporary 
arrangement is to place a board about four inches wide 
and just as long as the width of the window-sash beneath 
the latter.- Or, better, have a light frame covered with 
fine netting or wire-gauze, four or five inches wide, made 
to fit above the upper sash: the fresh air from without 



106 A MANUAL OF HYGIENE AND SANITATION. 

can now enter freely between the upper and lower sash, 
being reflected upward by the inner surface of the glass 
in the upper sash, and thus mixing with warm air before 
reaching the occupants of the room; while the frame at 
the top of the window becomes an outlet for the foul air, 
the interference of the netting or gauze preventing too 
rapid an outgo and consequent loss of heat. But in a 

Fig. 15. 




Currents in room lighted by gas and heated by open grate. 

climate such as our own, and in all cold countries, special 
measures must be taken during a large part of the year 
for warming the out-door air before introducing it into 
occupied rooms. 

Where we intend to depend most upon the third force 
of natural ventilation, viz., the movement of unequal 
weights of air, we must provide other openings for the en- 
trance and exit of the air than the windows and doors, so 



VENTILA TION AND HE A TING. 107 

that there will be a practically constant movement through 
the rooms in a given direction, that we may be sure the 
air is from a pure source, and that we may get the utmost 
service from our appliances. 

There is considerable difference of opinion as to the best 
locations for inlets and outlets, and as the conditions are 
necessarily different in every case and so many factors 
are to be considered, it is difficult to lay down any gen- 
eral rules. It should be an aim, however, to have the 
air well distributed throughout the room or rooms and to 
have no direct draughts from the inlets either upon the 
occupants or to the outlets. It is the writer's opinion 
that, usually, the outlets should be located near the top 
of the room, owing to the tendency of the used air to rise, 
and because, in unventilated rooms, the foulest air for 
some time after its contamination will be found nearest 
the ceiling. The products of combustion from lights, 
etc., will also practically all be in the upper strata of air. 
(Fig. 15.) If, however, provision is or can be made for 
a constant and sufficiently strong aspirating force in the 
outlet ducts, it may be advisable to withdraw the used 
air from near the floor level and below the inlet openings, 
though not in too close proximity to them, since in this 
way a more thorough distribution of the incoming air 
and a greater dispersion of its contained heat are secured. 
This is aptly shown in the illustration depicting the cur- 
rents in a room heated by a ventilating grate. (Fig. 16.) 
This principle is also involved in the well-known Smead 
system of ventilation and heating, which still further 
serves economy by carrying the foul air beneath the floor 
of the room from which it is taken, thus warming the 
floor with what heat the waste air yet contains and secur- 
ing the utmost benefit and value from the fuel. (Fig. 17.) 



108 A MANUAL OF HYGIENE AND SANITATION. 



The location of the inlets should depend on the tem- 
perature of the incoming air; if it is cold it should be 



Fig. 16. 




Currents in room heated by a ventilating grate. 
Fig. 17. 




Diagram illustrating the Smead system of ventilation. 



VENTILATION AND HEATING. 109 

admitted near the ceiling, so that it may diffuse and be 
partially warmed before reaching the inmates of the 
room; if it is warmed it may come in near the floor or 
below the middle level of the room. 

Where much fresh air is required it is better to have a 
number of inlets and outlets than one large one of each, 
as the distribution is then more certain. The total area of 
the outlets may be the same as that of the inlets, as the ex- 
pansion of the air is scarcely great enough to require a 
difference. The outlets should all be on the same level; 
otherwise the highest one will be the one of greatest dis- 
charge, and often the only one, the others possibly acting 
as inlets and drawing air from an impure source. As the 
temperature varies from time to time, and with it the cur- 
rent, some arrangement is needed for regulating the size of 
the openings of the inlets or outlets to suit the varying 
conditions. To supply 3000 cubic feet of air per head per 
hour a velocity of five feet per second will require an 
inlet-opening of twenty-four square inches for each person; 
but practically it is better to have a larger opening, as the 
above velocity is uncomfortable unless the air be well 
warmed. Outlet tubes should always be protected from 
cold and kept as warm as possible. 

As long as there is a fire in a grate or stove connected 
with a chimney there will be a constant upward cur- 
rent in the latter; and the area of the chimney's cross- 
section being known, and the velocity determined by the 
anemometer or by calculation, as already indicated, the 
amount of air passing out of the room in this way may 
readily be determined. In this connection it may be stated 
that a chimney may thus act as the only outlet and all 
other openings into the room may serve as inlets, especi- 
ally when the fire is brisk, the outgoing current, of course, 



HO A MANUAL OF HYGIENE AND SANITATION. 



being practically equivalent to the amount of incoming 
air. Moreover, the outgoing current may be so strong as 
to overtax the capacity of the inlets, in which case more 
or less of a vacuum will be created within, so that the 
outside pressure may cause down draughts in the chimney 
from time to time and a driving back of the smoke and 
gases from the fire into the room. The obvious remedy 
is to enlarge the inlet area by opening a door or window, 
or to lessen the exit draught by means of a damper in the 
chimney. On the other hand, the inlets may be so large 
and the current so strong that the air coming into the 
room cannot be properly warmed, in which case, again, 
the size of the outlet should be lessened by a damper, or 
there should be an increase in the efficiency of the heating 
apparatus. 

Artificial ventilation is that which is brought about by 
the intentional application of the above mentioned and 
other forces, and by means of special mechanical apparatus 
and devices, in contradistinction to natural ventilation, 
which may act independently of human cognizance and 
intention. It may consist in either extracting air from 
or forcing air into a room or building, or in both together. 
The object may be attained by heating the air by special 
apparatus in the outlet, or by warming the outlet itself, 
or by the use of a fan, a screw, or a steam or water-jet. 

When we wish to draw air from distant and non-com- 
municating rooms, the ducts may be led into a chimney 
below or just above a fire, or, better, into a flue or shaft 
alongside or encircling the heated chimney. When the 
exit ducts open into a chimney or smoke-stack the draught 
is greater just above a fire than below it, but the conduits 
should not enter near the top of the chimney, for there 
the extracting power is not so great and there is danger 



VENTILA TION AND HE A TING. \ 1 1 

of high winds blowing smoke and foal air back into the 
rooms. Outlet flues may be constructed alongside chim- 
neys that are being constantly used; they should be as 
smooth as possible interiorly, and should be as high as the 
adjoining chimney, to avoid down draughts. The open- 
ings from the rooms into these ducts should be as near 
the ceiling as possible, to get the benefit of the high tem- 
perature of the upper strata of air, unless, as previously 
indicated, there is certainty of the extracting force being 
constant and sufficiently strong, when the air may be 
taken from a lower level. 

In hospitals and other places where a constant and inde- 
pendent supply of heat can be afforded, extraction shafts 
apart from chimneys may be used. These extraction 
shafts may be heated by fires, steam pipes or steam-jets 
at the bottom, or by steam or hot-water pipes coiled around 
the sides. Some system like this is sometimes used in 
mines, where large quantities of air must be extracted. 
There is an entrance and an extraction shaft; large fires 
are constantly maintained at the bottom of the latter, the 
air is drawn down the former, diverted through all parts 
of the mine by partitions, and finally heated and carried 
up the extraction shaft. 

We may also use a jet of steam or water in place of 
heat to extract air through a shaft, the openings of the 
foul-air ducts being just behind the jet. It is said 
that a steam jet may thus set in motion over two hundred 
times its own bulk of air. Lastly, fans driven by steam 
or water-power have been employed to extract the air, 
though these are usually more efficient in forcing in air. 
One of 36 inches diameter at 600 revolutions per minute 
will propel or extract over 18,000 cubic feet of air per 
minute. 



112 A MANUAL OF HYGIENE AND SANITATION 

In ventilation by propulsion or driving in air, these 
large revolving fans are generally used. The advantages 
of this system of ventilating are the certainty as to the 
direction of current and amount of air supplied and the 
ease with which the quantity can be altered or measured. 
The disadvantages are the high cost of power in most 

Fig. 18. 




Air propeller, with electric motor attached. 



cases, the inconvenience or danger from prolonged stop- 
page from accidents to the apparatus, and some difficulty 
in distributing the air. For instance, if it be forced in 
through small openings or at too great a velocity it will 
not mix properly with the air of the room. The increased 
use of electric motors and lowered cost of running them 



VENTILA TION AND HE A TING. 113 

will doubtless serve to make this system of ventilation 
more common in the near future. 

House Warming. In cold countries there must be 
some resort to artificial heat in the winter season, and as 
this subject is more or less inseparably and closely con- 
nected with ventilation, it may be appropriately consid- 
ered at this time. Cold is depressing, uncomfortable 
and sometimes dangerous to the young and aged and to 
women whose habits of life keep them much in-doors; 
though well-fed, healthy adult men may not be much 
affected if accustomed to it. In this country we need a 
higher temperature in our houses than in Great Britain, 
on acount of our drier climate; evaporation and conse- 
quent cooling of the body take place more rapidly here, 
and so, while they are accustomed to a temperature from 
60° to 65° F., we find from 65° to 75° F. to be no more 
than comfortable. 

It needs but slight investigation to determine that we 
practically make use of but two kinds of heat — radiant 
and convected — in the warming of houses, and that of 
these the latter is by far the most generally employed 
and the most economical. Radiant heat, although it is 
considered to be the most healthful and warms an object 
directly without raising the temperature of the inter- 
vening air, has the disadvantages of utilizing but a small 
proportion of the fuel value, of decreasing directly as the 
square of the distance of the object from the source of 
heat, and of thus being available only in comparatively 
small apartments. Our best example of radiant heat is 
that which comes from open fires, though any highly 
heated object, as a stove, gives off more or less of it. 

Heat that is carried from one place to another by warmed 
masses of air, water or steam is said to be convected, and 






114-4 MANUAL OF HYGIENE AND SANITATION. 

because of the economy in its use and the ease of distri- 
bution, especially in large spaces, it is the kind most 
generally used. Conducted heat, which passes from 
molecule to molecule of the conducting substance, acts 
too slowly to be available to any extent in house-heating 
and may, therefore, be omitted from this discussion. 

Just here it may be remarked that, under present con- 
ditions, there are three things, any two of which we may 
have in cold climates or weather, but not all three to- 
gether, except in rare instances: they are good ventila- 
tion, efficient heating and cheapness. The reason for 
this is that any good system of ventilation necessarily aud 
continually carries off a large quantity of air and the heat 
it contains, which latter is lost for warming purposes and 
must be replaced at the expense of more fuel. A heat 
unit cannot be used at the same time to produce ventila- 
tion and to warm objects other than the air it keeps in 
motion. The principal aim,, then, in establishing any 
system of combined ventilation and heating must be to 
warm, introduce and carry off no more air than is neces- 
sary for the requirements of good ventilation and health, 
and to produce the heat for warming this air and the 
house itself as economically as possible, though care must 
also be had to secure evenness of distribution, absence of 
uncomfortable draughts, etc. 

The usual appliances for house-heating are open grates 
or fireplaces, stoves, and hot-air, steam and hot-water 
furnaces. To these may now be added electrical heaters, 
but the cost of maintaining the latter prevents their use 
at present by any but the wealthy. 

Ordinary grates and open fireplaces give practically 
only radiant heat, and render available only from 7 
to 12 per cent, of the fuel efficiency. They also heat 



VENTILATION AND HEATING. 



115 



directly only the surfaces facing them of objects in the 
room, leaving the remainder cold, and, by reason of the 
great current up the chimney, are also apt to bring in large 
quantities of air from without that has not been properly 
warmed and to thus cause chilling and injurious draughts. 
Where there is some additional means of heating the air 
before it enters the apartment and where the chimney cur- 
rent is controlled by a damper, they are valuable, not only 
for the good ventilation they produce, but for the pleas- 
ing effect of the exposed fire. 



Fig. 19. 




Jackson's ventilating grate. The outer casing is cut away to show space and 
surface for warming the incoming air. The air enters through the oblong inlet 
(a) and passes to the register opening (6) (in front) between and around the five 
smoke-pipes (c) above. 

To make open grates more effective for heating, the 
sides and top should be inclined to the back at an angle 
of 135°, so as to throw as many heat-rays as possible into 
the room; the fuel surface should be concentrated, and 
there should be a damper, to prevent too rapid combus- 
tion and too much heat and air escaping up the chimney. 
It is to be understood, of course, that the objects warmed 



116 A MANUAL OF HYGIENE AND SANITATION. 

by the radiant heat of the open fire do in turn give us 
convected heat by warming the air surrounding them. 

If, however, the back and sides of these grates be sur- 
rounded by a space through which air can pass and be 
warmed by the heat that would be otherwise wasted we 
shall have a much better apparatus, since we thus get 
both radiant and convected heat and may obtain from 
25 to 35 per cent, of our fuel efficiency. And if 
clean out-door air be let into this air-space and thus 
warmed before entering the room, the ventilation will be 
greatly improved, other inlets will be unnecessary, uncom- 
fortable draughts will be avoided and there will be enough 
heat provided for one or more apartments of moderate 
size. The air-chamber at the back should not be too 
small and there should be as much heated surface to 
warm the incoming air as possible. 

Stoves utilize a considerable percentage of the fuel — 
75 to 80 per cent, or more — but do not remove much air; 
so ventilation has to be provided for in some other way 
and is apt to be neglected. Stoves may also give off dan- 
gerous gases and products of combustion if not properly 
cared for or if the damper in the stove-pipe be entirely 
closed. There should be as much surface exposed as is 
possible without diminishing the combustion, so that there 
may be increased radiation and that much air may be 
warmed moderately rather than a little excessively. It 
is often advisable, especially in assembly or school-rooms 
and the like, to surround the stove with a sheet-iron 
cylinder extending from the floor toward the ceiling, and 
to bring in between this and the stove a supply of fresh 
air from without. This air becomes heated, and, passing 
out over the top of the cylinder or drum, gives a plen- 
tiful supply of convected heat and greatly improves the 



VENTILA TION A ND RE A TING. 117 

ventilation. A suitable outlet must, of course, be pro- 
vided. 

Carbon monoxide and other gases are known to leak 
through cast iron when it is too highly heated, so that 
stoves should not be allowed to become too hot. The 
production of carbon monoxide is most abundant soon 
after fresh fuel is added to the fire, and is evidenced by 
the characteristic blue flame burning above the coals. If 
at this time the escape of this gas into the outer air is pre- 
vented by the careless or accidental closing of a damper 
in the stove-pipe or chimney it is prone to pass through 
the top and sides of the stove in the manner indicated and 
to cause the serious and fatal results so often reported. 
Therefore, it should not be possible to cut off completely 
the draught from any coal-burning stove, nor should it- 
be materially lessened until combustion is well under way. 

Other objections to stoves that are allowed to become 
too hot are the excessive dryness of the atmosphere which 
they cause and the unpleasant odor due to the scorching 
of floating organic substances that come in contact with 
the hot iron. 

The fuel most commonly used in both grates and stoves 
is either wood or some kind of coal (bituminous, anthra- 
cite, or cannel); but gas may often be advantageously and 
more satisfactorily employed instead of any of these, since 
the heat can be had from it practically instantaneously, 
can be closely regulated in quantity, and can be promptly 
checked when no longer desired, and since there is no pro- 
duction of dust or ashes in the room. The main objection 
to gas is that for large rooms or prolonged or continuous 
heating it is usually more expensive than the other fuels; 
but this does not hold good for small rooms, nor some- 
times for isolated apartments or where the warmth is 



118 A MANUAL OF HYGIENE AND SANITATION. 

needed only temporarily; and it is very probable that 
before long fuel gas will be — it can be now — supplied at 
rates which will justify a much more extended use of such 
fuel. 

The ordinary kinds of gas-grates and stoves, especially 
those which consume the gas incompletely, should all be 
constructed with flues to carry off directly the products 

Fig. 90. 




Section of Backus' portable steam radiator for use with gas. 

of combustion, aud this particularly when any large quan- 
tity of gas is used. Theoretically, when the gas is burned 
in a properly adjusted Bun sen or " atmospheric " burner, 
the only combustion products will be carbonic acid and 
water, the former of which is rapidly diffused into the 
outer air, as has been shown, and is not likely to be harm- 
ful in any quantities thus produced, while the aqueous 
vapor is beneficial to the atmosphere rather than other- 



VENTILA TION AND HE A TING . 119 

wise. However, it seems that in practice even these 
Bunsen burners may sometimes give to the air a disagree- 
able odor (said to be due to the formation of acetylene), 
and so occasionally need flue connections. 

In this connection it may be interesting to describe one 
form of gas-heater which, so far as the writer knows, is 
unique. It is intended not only to consume perfectly the 
gas it uses, giving nothing to the air but carbonic acid 
and water, but also to destroy by fire the impurities of 
the atmosphere of the room, thus doing away with chim- 
neys or flues and the necessity of much ventilation. By 
a peculiar arrangement a continuous and large current of 
air is made to pass through the flame, thus burning the 
impurities, whether gaseous or solid. The heat of the 
burning gas is also used to convert a quantity of water 
into steam, which, by heating the containing chamber 
or coils of pipe, and these in turn the atmosphere sur- 
rounding them, in this way warms many times the vol- 
ume of air possible to heat by the flame alone. In 
addition, the humidity of the atmosphere is maintained 
by the evaporation of water from an open basin beneath 
the fire. 

The ordinary openings of any room are amply sufficient 
to allow the diffusion of the excess of carbonic acid — one- 
half escaping in this way, according to Roscoe, within 
ninety minutes — and to permit the ingress of enough air 
to supply fully all the needs of the inmates and of the fire 
itself. Experience and careful experiments seem to show 
that the claims of the inventor are well founded and that 
the apparatus is healthful in its operation and produces 
no harmful effects, even after continued use for several 
months. At any rate, there seems to be no reason why 
we may not purify the air by fire instead of by dilution 



120 A MANUAL OF HYGIENE AND SANITATION. 



and removal, the methods employed in the hitherto de- 
scribed systems of ventilation. 

Oil-stoves are now used quite extensively and, beside 
being portable, have the same advantages as gas-stoves, 
viz., that a considerable quantity of heat may be had 
quickly and just as long as it is desired, and at a fairly 
moderate cost. The combustion products necessarily 
mix directly with the atmosphere of the room, and 
where reasonably perfect burning is had, doubtless con- 
sist of little else than carbonic acid and water. One 
pound of oil, the hourly consumption of a rather large 
stove, will require about 150 cubic feet of air for its com- 
plete combustion, and will produce about twenty-five cubic 
feet of carbon dioxide. 

" We do not think that the experience has yet been 
accumulated which would enable us to speak positively 
of the innocuousness of a considerable admixture of car- 
bonic acid with the air we breathe; but the knowledge 
that in hundreds of cases oil-stoves are used for heating 
living rooms and even bedrooms, without apparent injury 
to the occupants, makes one feel fairly confident that the 
products of the complete combustion of hydrocarbons are 
not injurious when mixed with such an amount of air as 
is sufficient to dilute to a proper degree the respiratory 
products. . . . Experiments show that, provided 
the combustion of the oil is complete and that the ven- 
tilation is sufficient for the ordinary effects of respiration, 
the use of oil-stoves for heating purposes may be advanta- 
geously employed in both day-rooms and sleeping-rooms. 
The efficacy of oil-stoves is increased by placing over them 
a diffuser or radiator, so as to prevent the heated products 
ascending direct to the ceiling ; care needs also to be taken 
that only the better kinds of mineral oil are used; if 



VENTILATION AND HEATING. 



121 



inferior qualities of oil are burnt perfect combustion is 
more difficult to obtain." 1 

The above remarks, as far as they apply to the healthful 
use of the air, may probably be used with equal justice in 
regard to gas-stoves, provided that with such dilution 
their products give no obviously harmful or disagreeable 
results. 

Fig. 21. 




Spear's hot-air furnace. 

The heating apparatus thus far described is such as we 
are accustomed to employ for warming the air of single 
or, possibly, of adjoining rooms. Where a whole dwell- 
ing or other large building is to be heated it will usually 
be of advantage to do this from one point, and that not 

i Notter and Firth, p. 228. 



122 A MANUAL OF HYGIENE AND SANITATION. 

in any of the living apartments. In this way we shall 
have a centralization of fuel, both unburned and burning, 
and the ability to derive more heat from it; a lessening of 
the labor and attention bestowed on the fires; the obvia- 
tion of much dust, dirt and combustion-products in living- 
rooms, and, presumably, a more equable and satisfactory 
warming of the whole building. From such a central 
point the heat is distributed by hot-air, hot- water or 
steam, or by hot-air in combination with either of the two. 

Hot-air furnaces supply a large amount of convected, 
but no radiant heat. There is a very prevalent opinion 
that they are not healthful and that wherever possible 
they should be replaced by some other means of heating. 
But when properly constructed and cared for a hot-air 
furnace of the proper size is not only a good heater, but 
a powerful ventilating agent, for the large supply of air 
passing through it into the rooms above must in turn find 
an exit either through specially devised outlets or through 
the innumerable cracks and crevices around all doors and 
windows, and the ventilation will be accordingly. 

One frequent source of trouble is too small a fire-pot, 
giving insufficient heating surface and necessitating too 
rapid and too intense combustion of fuel. There should 
be a considerable expanse of surface, never too highly 
heated, so that large volumes of air will be moderately 
warmed rather than small quantities overheated and 
"burned." Air too highly heated is very dry and offen- 
sive to the senses — also, by taking excessive moisture from 
the body through the skin and mucous membrane and by 
exciting glandular activity, it increases the liability to 
frequent " colds " and congestions. Moreover, a large 
quantity of air moderately warmed will, perforce, be car- 
ried to all the rooms of the house, warming them equably 



VENTILATION AND HEATING. 



123 



and driving before it the air already there: whereas, a 
much smaller volume, excessively heated by the same or 



Fig. 22. 




Hot-air furnace, showing cold-air inlet and hot-air flues. Only one of the lateral 
branches of the main inlet above is shown. 



even a greater amount of fuel, will make its way along 
the channels of least resistance to a few favored rooms, 
overheating them and keeping the rest of the house cold, 



124 A MANUAL OF HYGIENE AND SANITATION. 

in addition to preventing any satisfactory natural ventila- 
tion. 

All joints in the furnace must be as near gas-tight as 
possible to prevent the combustion products passing from 
the fire-box or smoke-flues into the air-chambers and 
thence into the house. 

The furnace should be located near the cold side of the 
house — that is, the side on which the prevailing cold winds 
impinge, for it is said to be as difficult to drive the air 
ten feet against the wind as forty or fifty feet with it. 
It may also be well, if the basement ceiling is low, to place 
the ash-pit below the level of the basement floor, in order 
to give sufficient slope to the air-ducts; but in every case 
the space beneath the furnace should be cemented or laid 
in asphalt to prevent the drawing in of soil-air. 

The air-supply should not be taken from the cellar, 
even though the latter be apparently clean and free from 
any contamination with soil-air, but should come from 
a clean source out-of-doors, well above the ground-level 
and from the direction of the prevailing winds. The 
cold-air duct or ducts should be screened at the entrance 
to prevent the admission of refuse or vermin, should be 
arranged to permit of regular cleaning, should have a 
damper to regulate the supply of air and should have a 
cross-section of at least two-thirds of the combined area 
of the hot-air flues leading from the furnace. The im- 
portance of a large air-inlet cannot be too strongly empha- 
sized, for upon this feature may most depend the satisfac- 
tory action of the furnace. It may be desirable to provide 
for the filtration of the air through coarse cloth or fine 
wire-gauze, especially if there be much dust in the in- 
coming air. 1 

1 See page 99. 



VENTILATION AND HEATING. 



125 



If possible, the hot-air flues or ducts should not be too 
narrow in cross-section, but round or square, to lessen 
the friction, and for the same reason they should be as 
direct in their course and as nearly vertical as possible. 
They should be covered from the furnace to the register 
openings with asbestos or other non-conducting material 
to prevent the loss of heat that otherwise escapes from 
them into the cellar and between the partitions. Lastly, 
their register-openings into the rooms should not face the 
windows or prevailing winds, unless it be absolutely un- 
avoidable, for if they do the passage of warm air into 
the room will often be almost if not completely checked. 

The following table, from Coplin and Bevan, will indi- 
cate the proper size for hot-air flues and registers: 

First Floor. 



Size of room in cubic 


Size of pipe. 


Size of register. 


feet. 


If round. 


If square. 


If round. 


If square. 


Less than 1500 . . . 
1500 to 2000 .... 
2000 to 3000 .... 
3000 to 4000 .... 


7 inches 
8 
9 
10 


4x9 inches 

4x12 

4x16 

4x18 


9 inches 
10 
12 
12 


7 x 10 inches 
8x10 
8x12 
9 x 14 



Economy will be subserved in most cases by taking 
care to burn the fuel in hot-air furnaces quite slowly, 
since in this way larger quantities of air are warmed and 
more satisfactorily, and there is also less waste of heat 
through the smoke-flues and up the chimney. Moreover, 
it is the experience of the writer that by working the 
furnace in this way at low pressure, so to speak, the air 
from it will be less likely to become too dry, nor will it 
need the addition of so much moisture, something essen- 



126 A MANUAL OF HYGIENE AND SANITATION. 

tially necessary and yet most often neglected where too 
little air is excessively heated. 

The amount of water to be added also depends upon 
the humidity and temperature of the out-door atmosphere. 
When the latter is but little, if at all, below the freezing- 
point and is almost saturated, and when the in-door air is 
but moderately warmed, as suggested, the lack of added 
moisture may scarcely be noticed; while if the air without 
be at the same time dry and very cold, its actual content 
of water will be very little, and much added moisture 
will be needed to make it either comfortable or healthful, 
even though warmed to only a moderate degree. 1 

When it is necessary to carry heat for a considerable 
distance or to warm large buildings or blocks of buildings 
from a central point, it will be better and more economical 
to employ hot-water or steam as the heat-transmitting 
agent, on account of the high specific heat of the former 
and the great amount of latent heat held by the latter. 
" It is uneconomical to convey heated air any long dis- 
tance, as the amount of heat conveyed per cubic foot of 
air raised to any practical temperature is so small and so 
easily lost in transit. On this account Morin considers 
the availability (of hot-air furnaces) to be limited to a 
horizontal range of forty or forty-five feet from the heat- 
ing apparatus." 2 

An equal quantity of heat, viz., one thermal unit, is 
required to raise one pound of water or fifty cubic feet 
of air 1° F., and accordingly water will carry over four 
(4.21) times as much heat as an equal weight of air at the 

1 Most modern furnaces have a water-pan from which evaporation may take 
place freely into the warmed air, but the filling of this, when left to servants, is 
so often neglected that connection with the water-supply of the house by means of 
a float- valve or automatic cut-off would better serve to secure a constant supply. 

2 Stevenson and Murphy, vol. i., p. 117. 



VENTILATION AND HEATING. 127 

same temperature. " Farther, a greater effect is produced 
when water, in the form of steam, is made the carrier of 
heat, because one pound of water vapor at 100° C. 
(212° F.) will, in condensing to form boiling water, give 
off sufficient heat to raise the temperature of 5.36 pounds 
of water (or 4.21 X 5.36 — 22.5 pounds of air) from 0° 
to 100° C. (32° to 212° F.). m 

Hot-water heating may be by either the low-pressure 
or the high-pressure system. In the former, large pipes 
(generally four inches in diameter) are used and, the 
system beiug open to the air at its highest point, the 
temperature of the water is never much above 212° F. 
at any part of the system. The water circulates com- 
paratively slowly but, owing to the large volume, conveys 
much heat from the furnace to the places where it is 
needed. The high-pressure system employs small but 
very strong pipes, the water being completely enclosed 
from the outer air, wherefore it attains a high tempera- 
ture, usually about 3C0° F., and circulates rapidly. The 
necessary expansion is provided for by larger pipes partly 
filled with air at the top of the circuit. The maximum 
temperature is regulated by the proportion of pipe, usu- 
ally one-teuth, exposed to the fire. Either of the hot- 
water systems, but especially the loAV-pressure one, requires 
careful planning and setting to maintain evenness of circu- 
lation; and when the latter is complicated, as by many 
radiators at various levels, or where a number of circula- 
tions have to be supplied from the same boiler, it may be 
very difficult to maintain an even head and an equable 
distribution of heat in all. '• If properly constructed and 
the heating planned for when the house plans are made, 

1 Notter and Firth : Treatise on Hygiene, p. 231. 



128 A MANUAL OF HYGIENE AND SANITATION. 



this hot-water system is probably the most economical, 
both in fuel used and repairs demanded." 1 

Steam-heating methods are usually quite satisfactory, 
not only because of the large quantity of heat carried, but 
also since a rapid circulation is readily maintained, even 
under adverse circumstances. The size of pipe used will 
depend on the extent of the distribution, but the calibre 
of the radiator should always be considerably larger than 
that of the supply-pipes in order to favor condensation 
and the consequent liberation of latent heat, and every 
facility should be provided for the speedy return of the 
condensed vapor to the boiler. Care must also be taken 
to prevent the condensation occurring in such a way as 
to cause obstruction to the flow of the steam and the dis- 
agreeable thumping and noise that result. 

With either steam-heating or hot-water heating the 
direct, the indirect, or the direct-indirect method of 
radiation may be used. Of these the direct method — 
that is, where the radiators are placed in the rooms to be 
warmed — is most commonly employed in dwellings and 
other buildings of moderate size; but it is open to the 
objections that in itself it does not bring about a sufficient 
change of air, that the necessary inlets and outlets for the 
latter are rarely provided, and that when present they 
are independent of the heating system of the house. Of 
course, these objections are removed when the direct is 
combined with the indirect method, or when a plentiful 
supply of pure air is brought from without and is warmed 
by being made to pass through the radiators (either open 
or enclosed in boxing) before diffusing through the room. 
In the indirect method the radiators are placed outside 
of the room in suitable and convenient enclosures, into 

1 Coplin and Be van, p. 325. 



VENTILATION AND HEATING. 



129 



which fresh air is brought from out-of-doors and from 
which the warmed air is conveyed by suitable ducts to 
the respective rooms above. The direct-indirect method 
locates the radiators in the room, but encloses them and 
provides inlets to the boxing from without, so that the 



Fig. 23. 




Steam radiators and blower used in warming the clinical amphitheatre of the 
Medico-Chirurgical College of Philadelphia by the indirect system. (The casing 
of the radiators is not yet applied.) Tempering radiator at left ; warming radiator 
at right ; casing of fan between. 



entering air must pass over the heating surface and be 
warmed before entering the room. If properly arranged, 
both the indirect and the direct-indirect methods should 
furnish good and ample ventilation, the incoming warm 
air pushing the used air of the room ahead of it through 

9 



130 A MANUAL OF HYGIENE AND SANITATION 

the various openings in the walls of the room. Safety- 
valves on steam boilers prevent any clanger from explo- 
sions, and automatic therm o-regulators make it possible 
to maintain a practically even temperature throughout 
the house or building at all times. But there must be 
some arrangement for supplying additional moisture to 
the warmed air, just as with hot-air furnaces, for, con- 
trary to the opinion of mauy, neither the steam nor 
hot-water systems increase the atmospheric humidity. 

In the clinical amphitheatre of the Medico-Chirurgical 
College of Philadelphia the indirect system is employed, 
the details being as follows: The out-door air is brought 
from near the roof-level through a large shaft into the cold- 
air room, where it is moistened by a spray and whence it 
passes through a dust-filter, consisting of a double layer of 
fine wire-gauze. Thence it passes through tempering radi- 
ators (to partially raise the temperature) into the revolving 
fan, driven by its own engine, whence part passes through 
a second and larger radiator to be further warmed, and part 
below the latter, the two currents again uniting and, after 
mixing, passing through the flues into the amphitheatre 
above. In this the temperature is regulated by a thermo- 
stat, the latter governing a damper not shown in the cut, 
which always permits the same volume of air to pass into 
the flues, but controls the respective proportions of heated 
and tempered air, so that the mixture practically does not 
vary in temperature. In this way 900,000 cubic feet of 
air at a fixed temperature can be supplied per hour. 

For the private operating-rooms the system is the same 
except that the tempered and the heated air are not mixed, 
but each is carried by separate flues to double registers in 
the operating-rooms. In this way each operator can have 
the temperature that he desires in his room at any time. 



VENTILATION AND HEATING. 131 

In very large buildings it may be advisable or neces- 
sary, as above, to drive the air heated by the indirect 
method into the rooms (the plenum or propulsion system) 
or to withdraw it through special outlets by suction (the 
exhaust system). Of these the former is preferable, since 
the source from which the air is taken and the inflow 
through the heating apparatus are both more certain. 
However, the two methods may often be combined to 
great advantage. 

To determine the amount of radiating surface needed 
for any room we must multiply the volume of air to be 
heated per hour by the difference between its temperature 
in degrees Fahrenheit before and after warming, and 
divide this product by 50, the quantity of air in cubic feet 
raised 1° F. by one thermal unit. This will give the 
number of heat units required to warm the air. Then 
this quotient must be divided by the difference between 
the temperature of the radiating surface and that of the 
air when finally warmed multiplied by 1.75, the number 
of thermal units given off per hour by one square foot of 
hot-water or steam-pipe for each Fahrenheit degree of 
heat it loses. This will give the area of hot-water or 
steam-pipe required to warm the given volume of air. 
Thus, to warm 6000 cubic feet of air per hour from 20° 

to 70° F. will require 6QQ0 X ( 7Q ~~ 20 ) = 6000 heat 
1 50 

units, and if the surface of the radiator be 200° F., 

7-—— — =26.37 square feet will be the area 

(200° — 70°) X 1.75 H 

of radiating surface needed. To this must be added at 

least one-half square foot for each square foot of window 

glass and for each square yard of outer wall exposed. 



CHAPTER Y. 



WATER. 



Next to air, water is the most important of all sub- 
stances necessary to human life. While it has been often 
demonstrated that man may do without food for a consid- 
erable length of time, even for several weeks, he can prob- 
ably not survive much more than ten days without water. 
Not only must we have enough to supply the internal 
wants of the body and to replace that lost by excretion, 
evaporation and respiration, but from a sanitary point of 
view a plentiful supply is needed to maintain cleanliness 
of bodies, clothing and dwellings, and, oftentimes, to 
remove sewage, excreta, etc., from the vicinity of inhab- 
ited places. The care of furnishing water in abundance 
and of maintaining its purity is, therefore, entirely within 
the domain of the physician and the sanitarian. 

Before inquiring into the source whence we obtain the 
water that we use, it will be well to know what amount is 
required by the body for it* daily needs and how much 
for other necessary purposes, so that we may be able to 
judge not only whether a given source furnishes pure 
water, but also whether it gives a sufficient supply of it. 

The average adult should take from seventy to one 
hundred fluidounces per day for nutrition aud the internal 
needs of the body alone — about one-third of this being a 
component part of the food and the rest being taken in 
as drink. The writer is of the opinion that the average 



WATER. 133 

person does not imbibe enough water for the most health- 
ful action of his tissues and organs. Certain it is that in 
most cases the plentiful use of a good drinking-water not 
only greatly favors the body metabolism, but also mate- 
rially assists in the flushing out and carrying away of the 
various wastes and excreta of the system. 

In addition to this we must supply a sufficiency for 
cooking and for washing the food, body, clothing, house- 
hold utensils and parts of the house itself, and to remove 
the household waste and sewage through the drains and 
sewers provided for that purpose. Cleanliness is an 
essential requisite for the preservation of health, and 
cleanly habits should be inculcated among all classes of 
people and every facility provided for removing filth of 
all kinds from persons, clothes and dwellings. This, of 
course, cannot be done without a fair supply of water. 

Experience shows that about twenty-five gallons per 
head per day should be furnished for the above purposes, 
and as the quantity used by domestic animals, manufac- 
turing establishments, municipal needs, etc., must be 
added to this, fifty gallons or even more per capita 
should be supplied daily wherever it is at all possible. 
And though a supply that permits of excessive waste 
may be inadvisable and expensive, both to provide and 
by increasing the cost of carrying it away after use, it is 
always better to have too much than too little and the 
disadvantages of too scanty an amount are much greater 
than those of one too large. 

It should be stated, however, that most foreign cities are 
supplied with much less water per capita than is apparently 
needed by the municipalities of this country, and yet they 
seem to have an abundance for all necessary purposes and 
the requirements of public health. For instance, London, 



134 A MANUAL OF HYGIENE AND SANITATION. 



with a population of over five millions, has an average 
daily supply that but slightly, if at all, exceeds that of 
Philadelphia with one-fourth the number of citizens; 
while Berlin, which is of about the same size as Phila- 
delphia, had in 1893 an average daily supply of filtered 
water of only 18.4 gallons per head, all of which was sold 
to the consumers by meter, but to which must be added 
considerably more that was from wells and was exclusively 
used for manufacturing purposes, running machinery, etc. 
It cannot be doubted that the quantity wasted in many of 
the cities in this country is excessive, and that the cost of 
supplying that part of the total quota would go a long 
way toward improving and rendering pure and safe the 
remaining part that is absolutely needed. Whether the 
compulsory use of water-meters is the best way of bringing 
about an improvement in this respect remains to be de- 
termined; but it is also a question whether our larger 
cities, with rapidly increasing populations, can afford to 
use the means necessary to' safely purify the enormous 
quantity of water now daily supplied to their respective 
consumers. 

As only a small portion of the quantity indicated above 
is required for the internal needs of the body, it has been 
suggested that two kinds of water be furnished to each 
dwelling — one for drinking and cooking purposes and 
for the washing of the body, to which especial attention 
as to purity should be given; and another kind for all 
other purposes, its composition and purity being dis- 
regarded, excepting possibly as concerns the hardness. 
This would enable the authorities to furnish a water purer 
than usual for those needs wherein purity is of the greatest 
importance, and would obviate the necessity of furnishing 
pure water abundantly for all purposes; but the scheme 



WATER. 135 

would necessitate a double set of reservoirs, mains, dis- 
tributing apparatus, etc., thus materially increasing the 
cost; and there would always be present the danger of 
the careless or ignorant using the impure water for bodily 
needs, thus increasing the risks and bad results that we 
wish to avoid. Therefore, wherever there can be an 
abundance of pure water for all personal and domestic 
purposes, if the authorities but take pains to furnish it, 
it will be best to have but one supply in dwellings, and 
this as pure and abundant as money and the highest sani- 
tary skill can make it; though there may be little or no 
objection to using a different water for factories, stables, 
city functions, etc. 

As to the question of supply through meters, it may be 
added that the suggestion has been made that the regular 
charge for water begin only after a certain specified amount 
per month per capita or per household has been furnished 
free or at the lowest possible cost, thus doing away with 
the objection that those who need the water most for per- 
sonal and sanitary uses would be tempted to economize too 
much if they had to pay for all they consumed. Whether 
a city could afford to do this would have to be carefully 
considered, and would probably depend largely upon local 
circumstances. 

Another method is "to assess every owner of premises 
where water is used a certain moderate, but fixed, sum 
yearly, even though water used at the regular rate per 
thousand gallons does not call for so much charge." 
This sum would, of course, be considerably less than the 
rate necessary under the old method, and in itself would 
be an inducement to the introduction and use of meters. 

Experience shows that meters greatly reduce the total 
consumption of water, since it is to the direct advantage 



136 A MANUAL OF HYGIENE AND SANITATION. 



of each consumer to check needless and reckless waste on 
his own premises, which is otherwise neglected because it 
does not affect the yearly charge and cost of water to him. 
Meters, wherever used, seem to have materially reduced 
the cost of the water to the consumer and the cost of sup- 
plying it on the part of the city or other owners of the water- 
works. It may, however, often be advisable for the latter 
to own and control the meters, as do gas companies. 

Sources. Practically, all drinking-water has at some 
time or other fallen upon the earth from the atmosphere in 
the form of rain, hail, snow or dew ; but when we speak 
of its sources we have reference rather to the immediate 
place or locality from which we collect it for use. The 
rain on reaching the earth is disposed of in three ways : 
part at once evaporates and goes back to the atmosphere, 
part flows off according to the slope of the ground and 
collects in pools and streams, and part sinks into the soil. 
The ratio which these three portions will bear to one 
another will depend on the time, place, character of soil, 
intensity of rainfall, etc. Consequently, we may classify 
the sources of potable waters — as Leffmann does — as fol- 
lows : Rain-water, collected immediately as it falls in 
the form of rain, dew, snow, etc.; surface-water, col- 
lected in ponds, lakes, streams, etc., and in free contact 
with the air; subsoil or ground-water, derived mainly 
from the rain or surface-water of the district, but which 
percolates and flows through the subsoil and is, there- 
fore, not exposed directly to the atmosphere; deep or 
artesian-water, which is separated from the ground-water 
of the district by one or more practically impermeable 
strata, and which accumulates at a considerable depth 
below the surface. Springs are caused by the outcrop- 
ping of water-bearing strata below the level of the water- 



WATER. 



137 



line in them, and furnish either subsoil or artesian-water, 
according to the kind contained in the respective strata. 

Rain-water is, theoretically, the purest at our command, 
but in reality it takes up many impurities from the air in 
its fall, especially in the neighborhood of human habita- 
tions and communities, and by the time it reaches the 
earth contains ammonia, nitrous and nitric acid and, in 
towns, sulphurous acid, soot, many bacteria and even 
microscopic plants. Moreover, and especially after con- 
tinued dry weather, the collecting surface upon which it 
falls is apt to be covered with dust and impurities of all 
kinds, which, being taken up by the rain water, tend to 
make it unfit for use. But if there be some arrangement 
for turning aside the first portion of the rain, it contain- 
ing the most of the impurities, and if the remainder be 
filtered and stored in proper receptacles the water may be 
of excellent quality. 

The main objection, however, to the sole use of rain- 
water is that dependence is placed upon a very uncertain 
source, and one which is especially apt to fail when an 
increased supply is most needed. The average rainfall 
in Philadelphia is about thirty-nine inches per year; in 
very wet years it is about one-third more, and in very 
dry years about one-third less than the annual average. 
Each inch of rainfall gives 4.67 gallons per square yard 
of area on which it falls, equivalent to 22,617 gallons per 
acre. Allowing sixty square feet of collecting surface 
per head, and counting the loss by evaporation, etc., at 
20 per cent., an annual rainfall of thirty inches would 
give only about two gallons per head per day, or just about 
enough for cooking and drinking purposes and none for 
the other needs of the household. 

Bain-water may be collected from roofs or from a plot 



138 A MANUAL OF HYGIENE AND SANITATION. 

of ground paved for the purpose with slate or cement, and 
be led by proper conduits to a cistern. It should be filtered 
(Fig. 24) before passing into the cistern, while the cistern 
itself should be such as to give no unpleasant taste or in- 
jurious substance to the water, should be so situated that 
it will receive no rubbish or impurities and that the water 
may be kept cool, and should be cleaned regularly and 



Movable covering stone. 



Fig. 24. 

Paving. 



Level of ground. 



^^////y////////////////////////////^^m= ? ^=s^^i^^ 




Cistern. 



A simple filter for rain-water. (Notter and Firth.) 1 

often enough to keep the water sweet and wholesome. As 
rain-water contains considerable carbonic acid and other 
gases, its solvent powers are increased, and cisterns should 
not be lined with lead, copper, zinc or iron, lest these 
metals be taken up by the water and produce harmful 
results. These remarks do not apply to the so-called 
rustless iron now much used; but galvanized iron should 

1 This illustrates a filter for an underground cistern. One of similar construc- 
tion can be readily made for cisterns above ground, the latter being always 
preferable. 



WATER. 



139 



not be used, as it may give up zinc to the water. Cement 
should also be used in lining brick or stone cisterns instead 
of mortar, as the latter may add lime to the water and 
render it hard. 

Underground cisterns for storing rain-water should be 
avoided, where possible, since they are liable to soil-air or 
sewage contamination unless absolutely air- and water- 
tight. Nor should the overflow pipe from a cistern open 
into a soil-pipe or sewer-pipe or drain, but always into 
the open air, since water is so prone to take up the vari- 
ous kinds of gas with which it comes in contact and the 
sewer-air might readily contaminate the entire contents 
of the cistern. 

Rain-water is especially valuable in cooking and wash- 
ing, on account of its softness, water being called " hard" 
when it contains an excess of the salts of calcium or 
magnesium in solution. Hardness due to the presence 
of calcium bicarbonate is said to be temporary, because 
it is removed when the water is boiled, one molecule of 
carbonic acid being driven off by the heat and leaving the 
insoluble calcium carbonate behind. Hardness due to the 
other salts of calcium and magnesium is called permanent, 
because it is not lost by boiling. In cooking with water 
temporarily hard the chalk is precipitated upon the sides 
and bottom of the vessel and, being a non-conductor, 
prevents the passage of heat and thus wastes fuel. 

Hard water may also prevent the proper softening of 
certain foods, such as peas and beans, in cooking. In 
washing and laundry work the calcium and magnesium 
salts unite with the fatty acids of the soap and prevent 
the formation of a lather; for instance, one grain of chalk 
wastes about eight grains of soap. As we do not call a 
water hard unless it contains more than ten grains of chalk 



140 ^ MANUAL OF HYGIENE AND SANITATION 



or its equivalent per gallon, and as rain-water rarely has 
more than one-half a grain per gallon, it is easily under- 
stood why the latter is so valuable in the kitchen and 
laundry. 

A water-supply taken from rivers or smaller streams 
not polluted by the refuse and sewage from towns, fac- 
tories or cultivated farm lands higher up the stream, 
may be fairly pure and safe to use. The best water of 
this kind will be from hilly and uninhabited, uncultivated 
tracts, with many small streams fed by constant springs 
and uniting to form rapid creeks and rivers. Such water 
may be tinged slightly with vegetable or mineral matters, 
but, in general, such coloration is harmless. For storage, 
dams may be thrown across convenient valleys, thus im- 
pounding the water and at the same time keeping it 
exposed to the oxidizing and aerating influence of the 
atmosphere and allowing the solid impurities to settle to 
the bottom. Small lakes or ponds may be used to add to 
supplies of this kind, provided they be not stagnant nor 
have much decaying matter along their banks. 

On the other hand, water from a stream which has 
received the sewage from a village or town of any size, or 
the refuse of factories, or the drainage from large tracts 
of cultivated land, should be considered as at least suspi- 
cious. River-waters are generally hard and may contain 
any of the minerals in the soils which they drain or over 
which they pass; but the great danger is from impurities 
of animal origin poured into them along their course. 

It is not safe to depend altogether on the self-purifica- 
tion of sewage-contaminated rivers, as was formerly done, 
though a considerable portion of the sewage and filth un- 
doubtedly is removed, part by oxidation by the air in the 
water, especially in streams flowing over dams, rapids, etc. ; 



WATER. 



141 



part by subsidence or deposition along the banks; part by 
fish and animalcule, and much by the myriads of sapro- 
phytic bacteria which such waters contain. If no addi- 
tional pollution is added, what is left unchanged by the 
above purifying agencies is still further diluted by the 
supplies of pure water that every stream receives from 
springs along its banks and in its bed and from tributary 
streamlets, so that, though the water may never be as pure 
as it was originally, it may possibly become or, by proper 
filtration or treatment, be made a safe and usable water. 
But where the proportion of filth exceeds a certain per- 
centage, or where sewage is being constantly added, the 
contained oxygen is rapidly used up and oxidation ceases, 
fish and animalcule cannot live in the water for lack of 
sufficient oxygen, and though the heavier and larger par- 
ticles of the sewage sink to the bottom or stick to the sides, 
they are stirred up and set in motion by any increase in 
the velocity of the current. The only remaining agents 
active in the destruction of the foul matter are the bac- 
teria, but in themselves they are often insufficient for the 
task, aud the water thus polluted is entirely unsafe for use. 1 
The greatest danger from sewage contamination, how- 
ever, is that it may at any time add to the water the 
germs of infectious disease, which, multiplyiug rapidly 
and not being surely removed or destroyed by the ordinary 
agents or methods of water-purification, greatly increase 
the risks to health. It often fortunately happens that, 
owing to the hostility of the saprophytic bacteria of the 
water, or to the presence of certain chemical substances, or 
to other unfavorable conditions, as of temperature and the 



1 According to the report of the Rivers Pollution Commission some years ago, 
no stream in England is long enough to satisfactorily purify itself of the sewage 
contamination it is liable to receive. 



142 A MANUAL OF HYGIENE AND SANITATION 

like, these pathogenic organisms do not multiply as rapidly 
as they otherwise would and are, therefore, not plentiful 
enough to do much harm. But, as it never can be certainly 
told when a water so contaminated becomes safe for use 
again, and as the population of most towns and their con- 
sequent sewage production is constantly increasing, while 
the quantity of water in the receiving streams remains 
about the same or is diminishing from year to year, the 
use of such water should be avoided if possible, or, if it 
must be used, it should be purified and made reasonably 
safe by the most scientific and efficient means and methods 
available. 

Water from large fresh-water lakes will be of the best 
quality, provided it be taken from a point sufficiently 
distant from the shore to escape all danger of sewage 
contamination. Chicago apparently lowered the mortality 
percentage from typhoid fever from 7.2 in 1891 to 2.1 in 
1895, and 3.2 in 1896, by preventing as far as possible 
the discharge of sewage into Lake Michigan and by taking 
the water-supply from the lake at a minimum distance of 
one mile instead of 1400 feet from shore, as formerly. 
Water from small lakes or ponds, and even from storage 
reservoirs, may become offensive to taste and smell through 
the growth in them of minute vegetable organisms, such 
as the algae, though it is not known that these are preju- 
dicial to health. 

Ordinarily, water loses much organic matter as it per- 
colates through the soil, but takes up considerable carbonic 
acid from the soil- air, which increases its solvent powers 
so that it may also dissolve some of the mineral constitu- 
ents of the soil through which it passes. When these 
mineral substances become so great in amount as to give 
the water a decided taste or medicinal properties, we call 



WATER. 



143 



it a mineral water; but when the inorganic matter does not 
render it objectionable to the taste or too hard, the water, 
whether subsoil or artesiau, will usually be quite safe and 
usable, in so far as the mineral matters are concerned. 

Attention has already been called to the pollution of 
the soil. How, then, can the water in passing through it 
lose its organic contents and become pure ? Partly by 
mechanical nitration, but mainly through the combined 
action of the saprophytic bacteria and the oxygen of the 
soil-air, which rap dly convert the organic impurities, 
both suspended and dissolved, into simpler and harmless 
end-products. The substances of vegetable nature are 
ultimately resolved by these agencies into carbonic acid, 
water, etc., while those of animal origin and containing 
nitrogen give rise to the various ammonia compounds, or 
may be further oxidized into nitrous and nitric acids and 
their salts, all entirely harmless in the proportions in 
which they are found' in the percolating ground-water, 
but all of great value as nutrients for the higher plant 
life of the soil. 

The rate of percolation has much to do with the com- 
pleteness and perfection of this action, for ample time 
must be had for the organic decompositions to occur. 
Therefore, anything that retards the downward flow of 
water favors its purification, and anything that increases 
its movement decidedly affects for the worse its ultimate 
quality and character. 

The importance of this biologic soil action can scarcely 
be overestimated, and the student should endeavor to 
appreciate not only the bearing which it has in the great 
scheme of nature's adaptation of means to ends, but also 
the importance of our utilization of it in the artificial puri- 
fication of our environment and the disposal of our waste 



144 A MANUAL OF HYGIENE AND SANITATION. 

matters. We mast understand, however, that for every 
soil only a definite amount of work can be accomplished 
by the agencies mentioned and under the conditions exist- 
ing at any given time. In other words, there is here also 
a limit of permissible impurity, and if this limit is exceeded, 
the conditions become unnatural, the bacterial and chemic 
action is inadequate, and the descending water is not 
thoroughly purified as it percolates through the over- 
charged soil. 

The subsoil-water slowly sinks through the ground until 
at some level or other it reaches an impermeable stratum, 

FTG. 25. 




Diagram to represent the difference between shallow and deep wells, and be- 
tween the high-water and low-water level of the ground-water, a, soil and gravel ; 
b, clay or rock ; c c, high- water, and d d, low-water level. 

where it is retained in natural basins or escapes at some 
outcropping of the stratum below the water-level, thus 
forming a spring. (Fig. 25.) The level of the water in these 
underground reservoirs is constantly changing, according 
to the season, rainfall, discharge from springs, etc., though 
the variation for any given place is usually regular and 
differs little from year to year. It is from wells sunk 
to these water-bearing strata and from springs that water 
is obtained for the majority of people who do not live in 
towns or cities supplied by water-works. These under- 



WATER. 



145 



ground bodies of water are in constant motion toward one 
or more outlets at more or less distant points, but the cur- 
rents are usually quite sluggish owing to the friction and 
capillary force of the particles of soil through which they 
pass. For the same reasons the surface of the water is not 
exactly horizontal but curved, the curve being sharpest 
near the outlet, and the difference in level between high 
and low water is least near the outlet; also, the higher 
the level the greater the fall to the outlet and the greater 
the discharge. (Fig. 25.) 

The remarks regarding the purity of this underground 
water do not hold good for water from ordinary shallow 
wells under fifty feet in depth — provided they do not pass 
through an impermeable stratum — or from springs where 




Diagram to represent difference of percolation about cased (d) and uncased 
(e) wells, a, soil and gravel ; b, clay or rock ; c, cesspool. 

the water passes almost directly from surface to outlet, 
for in both cases the complete filtering action of the soil 
and the removal of organic matter by the prolonged action 
of the saprophytic bacteria are likely to be wanting. 
Especially about human dwellings, where wells are 

10 



146 A MANUAL OF HYGIENE AND SANITATION. 



commonly located for the sake of convenience, is filth 
and pollution apt to be carried into the water, for sewage 
and dirt of almost every kind accumulate in constantly 
increasing quantity in the soil about a house, and always 
tend to exceed the limit of permissible impurity. There 
is also the ever-present danger of the water receiving the 
specific germs of disease from the human wastes of the 
household no matter how clean the surrounding soil may be. 

Owing to the lessening of lateral resistance the surface- 
water passes rapidly and almost directly into the well (un- 
less the wall of the latter be made water-tight to almost the 
full depth), and may carry with it solutions of all the impu- 
rities polluting the soil about the mouth; and as wells drain 
a very considerable area — Parkes says one, in ordinary 
soils, whose radius is equal to four times the depth of the 
well — there are few wells about which such an area is not 
subject to dangerous pollution. Moreover, the influence 
of pumping or other sudden withdrawal of water from the 
well is even more important, since it extends a distance 
from fifteen to one hundred and sixty times the temporary 
depression of the water-level, and impurities may thus 
be drawn into the well which would ordinarily tend to 
flow away from it. (Fig. 27.) 

Excepting the bacteria, which pass freely through 
almost all soils when resistance to the water-current is so 
markedly diminished, only such parts of the pollution as 
can be dissolved may reach the water in the well; and it 
is a strange fact that many waters thus polluted are spark- 
ling and clear, with a pleasant taste and no bad odor, so 
that all suspicion as to their true character may be want- 
ing. Moreover, even though specific disease germs be 
absent, there is always danger that the contamination 
may become so concentrated as to produce serious results, 



WATER. 



147 



and this may occur in various ways : (a) The well may be 
so deep or the character of the soil such that in ordinary 
weather the liquid passing through the soil is so purified 
that it gives no bad properties to the water; but if the soil 
is being continually infiltrated with dangerous impurities 
and if at last heavy rains or continued wet weather super- 
vene, there may be more and more of these impurities 
dissolved and carried into the well until the proportion of 
harmful matter in the water passes the safety line and 




Depression of water in shallow well by pumping. A, well ; B, cesspool ; 
C, underground water-curve. (After Field and Peggs.) 



we have marked illness or increased predisposition to dis- 
ease among those using the water as a result; or (6) in 
continued dry weather the ground- water may be lowered 
to such an extent that the impurities that were formerly 
well diluted become concentrated and dangerous enough 
to cause sickness, even though there be no unusual pollu- 
tion of the soil about the well; or (c) the water-level in 
the well being suddenly or persistently lowered, a greater 
area is drained and additional collections of sewage may 
flow into the well. (Fig. 27.) 



148 A. MANUAL OF HYGIENE AND SANITATION. 



Deep wells are those over fifty feet in depth, or which 
go through an impermeable stratum, aud so, in the latter 
case, do not get their supply from the subsoil-water. 
Artesian wells are very deep wells, piercing one or more 
impermeable strata. 

Sometimes the water rises and flows out of the mouth 
of a deep well, in which case the supply is drawn from a 
water-bearing stratum between two impermeable ones, 
and which has its only outcroppings higher than the top 
of the well. (Fig. 28.) The water accumulates in this 

Fig. 28. 




Diagram to represent the spontaneous flow of deep or artesian wells, b and c ; 
a a, water-level in deep pervious strata, ff; a, intermittent spring at outcropping 
of f f above impermeable stratum, is e ; d, shallow well in upper pervious strata. 
(Wilson.) 

natural reservoir above the level of the well-mouth, and 
is forced out. as soon as the opening pierces the uppermost 
impermeable stratum. Deep well-water is apt to be of 
much better quality than that from shallow wells, since it 
usually represents the total percolation from a very large 
extent of ground surface, in comparison to which the com- 
bined areas and amount of pollution within its limits are 
insignificant, the possible impurities in the water being con- 
sequently reduced by dilution to much below the danger- 
point. It is for the same reason that there is such a dif- 



WATER. 149 

ference in the quality of spring-water and that from most 
shallow wells. Though they seem to have a common 
source, one is the composite water of a large district, of 
which the average impurity or contamination per unit 
of surface may be infinitesimal; the other is mainly the 
special percolate from a limited area, which is, for the 
reasons given, particularly liable to be highly and dan- 
gerously polluted. 1 

Artesian or deep well-water will also likely be very free 
from organic matters but possibly heavily charged with 
mineral salts. Should these latter not be present, the 
water will probably be of excellent quality, though if the 
well be very deep it may be too warm for immediate use 
as a potable water. 

Frequently well-water, and that most often from shallow 
wells, is the only kind available, especially in country dis- 
tricts. In such cases care must be taken that impurities 
are kept out of the well by all possible means. If this be 
doue, water may often be had of safe and excellent quality. 
The area about all wells should be kept clean, and the 
well should be as far as possible from any source of con- 
tamination, especially if the latter be a constant one. 
Wells should be walled or cased, shallow wells to below 
the water-level and deep wells to the first impermeable 
stratum if possible, in order to cause the water to perco- 
late through as much soil as possible before entering the 
well, in this way checking the rapidity of its descent and 
prolonging the biologic action of the top-soil. 2 Wells 

1 Of course, the water in shallow wells, as in others, is heing continually 
changed by the onward movement of the underground current ; but where this 
is slow in comparison with the percolation from the surface, the impurities of the 
latter will be in excess in the well-water. 

2 As the saprophytic and nitrifying bacteria are only found normally in the 
first few feet of top-soil, where the conditions are favorable to their existence 






150 A MANUAL OF HYGIENE AND SANITATION 






should also have a good curb, to keep out splashings 
and drippings of muddy or dirty water. 

We must not forget that wells drain a large area. As 
the ground-water has a constant movement in the direc- 
tion of natural outlets, the well should be so located that 
the current flows from it toward any near-by cesspool or 
other source of pollution. The direction of the under- 
ground current can generally be determined by noting 
the location of the nearest spring or water-course, by 
observing the dip of the underlying strata, or by digging 
holes at equal distances about the well and dissolving salt 
or an aniline dye in them in turn and testing the water 
from the well after a time for the salt and color. If a 
well be much deeper than a neighboring cesspool it may 
drain from the latter, even against the ground-water cur- 
rent, especially if the water in the well be suddenly low- 
ered. Again, dangerous impurities have sometimes been 
carried into wells from long distances through fissures or 
crevices in the rock. 

The water from the well should be frequently tested for 
chlorides and nitrates, these indicating sewage contamina- 
tion, and this should be done especially after heavy rains 
and also when the water in the well becomes low. The 
taste and odor of the water should also be noted after 
standing for a time or being heated. Some other sources 
should be sought whenever the tests show contamination 
or when there are cases of infectious disease near at hand. 



and growth, we cannot expect to have any further action by them after the 
water reaches its underground level and begins to move toward its outlets. Nor 
will there be any filtration in this onward progress, for that has already been 
accomplished in the upper layers. It is for this reasou that the filtrate from cess 
pools and similar pits is not organically purified, but is especially obnoxious and 
dangerous as it traverses the soil, for the bottoms of such pits are usually below 
the biologic level, and there is also a lack of the oxygen necessary to maintain 
the action of the nitrifying bacteria. 



WATER. 151 

Boiling the water and filtration are always to be recom- 
mended whenever there is any suspicion as to impurity 
or infection. 

Shallow or subsoil wells in thickly settled towns should 
not be used to supply drinking-water or cooking- water, 
as the soil is always more or less saturated with filth and 
sewage, and it is practically impossible in such places to 
locate a well which will not be in constant danger of re- 
ceiving harmful impurities from some source or another. 

The decision as to the quality of any water must in each 
case be determined by all the circumstances available 
which relate to it, and these should all be thoroughly in- 
vestigated before rendering an opinion, as some of them 
may counteract the others. However, other things being 
equal, the value of a water will probably be in accord with 
the following table: 

r\. Spring-water, ) Very- 
Wholesome < 2. Deep well-water, ) palatable. 

^3. Water from unpolluted streams, "I Moderately 

Suspicious -f 4 ' stored rain-water, J palatable. 

1 5. Surface-water from cultivated land, ^ 

Dangerous i 6 ' Sewage-polluted river- water, r Palatable. 

w. Shallow well-water, 

A good potable water should be perfectly clear, free 
from odor or taste, cool, well aerated and, if possible, 
soft, or with only a mild degree of hardness. Circum- 
stances must determine the amount of dissolved matters 
permissible; what is an excess in one case might not be 
so in another. 

We may also classify waters as follows: 1. Pure and 
wholesome water. 2. Usable water. 3. Suspicious water. 
4. Dangerous water. (See table on page 197.) Pure waters 
and usable waters may be used without filtration; those 
of the third class should be filtered before distribution, 
and also at the house before use, if possible, and a purer 



152 A MANUAL OF HYGIENE AND SANITATION. 

source sought out or all sewage-pollution prevented. 
Those of the fourth class should not be used at all except 
when it is absolutely unavoidable, and then only after 
purification by all the means at command. 

Inasmuch as most large cities must from necessity fur- 
nish a water of the second or third, and occasionally even 
of the fourth class, such water should be purified as much 
as possible before distribution by storage for a time in set- 
tling reservoirs and by some effective system of filtration, 
combining these with chemical treatment, if necessary. 
As much of the organic matter is oxidized, and many of 
the pathogenic bacteria are destroyed by saprophytes and 
other causes while the water is standing in the settling 
reservoirs, and as properly constructed and well-managed 
filters are even more efficacious to this end, a water origin- 
ally suspicious or worse may often be made quite usable 
by the above means properly employed. Not only must 
the storage reservoirs and filtering apparatus be kept clean 
and in good working order,' but care must be had that 
the distributing apparatus does not allow soil-air or 
sewer-air or sewage to be drawn in through leaks in the 
mains at times when the flow is intermittent, and that 
lead pipes are not used in the houses if the character of 
the water is such that it acts on that metal. 

Diseases Caused by Impure Drinking-water. A pol- 
luted water may carry the organisms of infectious diseases, 
or it may produce or favor the development of diseases 
which are not due to specific germs. In addition to this, 
and of at least equal importance from a sanitary point of 
view, is the depressed state of the system that the habitual 
use of impure drinking-water causes, and the predisposi- 
tion to disease that ensues. By the power of accommoda- 
tion and through long habit, a community may become 



WATER. 153 

so protected against an impure water as to manifest no 
striking symptoms, while strangers may be seriously 
affected by it; but even in such a case the condition of 
those habitually using the water will probably be more 
or less depressed and far from good. 

The non-infectious diseases likely to be caused by im- 
purities in the drinking-water are primarily those affecting 
the alimentary tract, as dyspepsias, diarrhoeas, and other 
disturbances having their origin in severe gastric or intes- 
tinal irritation. So, also, impure water, even though it 
does not contain the actual germs, may have much to do 
in bringing on an attack of typhoid fever or specific dys- 
entery by so irritating the intestine as to make it especially 
receptive to the cause of the disease when introduced from 
another source. 

Large quantities of the sulphates of calcium and mag- 
nesium are thought to have special influence in causing dys- 
pepsias, with loss of appetite, pain at the epigastrium, etc. 
An excess of iron in water is also prone to produce consti- 
pation, headache, loss of appetite, and malaise. Goitre 
and the formation of vesical calculi are each supposed to 
be due to mineral or inorganic impurities, though the true 
relatiou of impure drinking-water to these diseases is still 
unsettled. " It has long been a popular opinion that 
drinking lime-waters gives rise to calculi of the oxalate 
and phosphate of calcium," and the " opinion that impure 
water is the cause of goitre is as old as Hippocrates and 
Aristotle." Further study of the principles underlying 
the new treatment of goitre with glandular extracts may 
make it easier to determine whether bad water has or has 
not a causative influence in the production of this disease. 

Diarrhoea may be produced by any of the following im- 
purities in water : Suspended substances of any kind, but 



154 A MANUAL OF HYGIENE AND SANITATION. 



especially those of fecal origin; dissolved animal, vege- 
table or mineral matters, and fetid gases. The diarrhoea 
produced by any of these contaminants may be so severe 
as to simulate true dysentery and cause doubt as to the 
diagnosis. 

Certain metals maybe taken up from the earth's strata, 
or from the lining of cisterns, etc., and may produce their 
characteristic and poisonous symptoms in the system. 
Lead is one of these metals, and it will be well to note 
here the waters that are especially apt to take up this 
metal. Pure waters and those containing much oxygen 
act powerfully on lead, as do those containing organic 
nitrates and nitrites, especially ammonium nitrate. 
Waters containing carbonic acid and the salts of lime and 
magnesia and those free of absorbed gases act least on 
lead, and carbonic acid seems even to protect lead by 
forming an insoluble carbonate on its surface. Lead is 
more easily dissolved if other metals are in contact with 
it, probably owing to electrolytic action. Lead should 
not be used for pipes nor to line cisterns unless suitable 
tests show that the water does not affect it, nor should 
any water be used in which the tests show more than one- 
twentieth of a grain of lead per gallon. Even water con- 
taining carbonic acid may take up lead for a time from 
new pipes until the insoluble carbonate is formed within 
them, and it has been shown that in some cases wherein 
cold water does not act upon the metal, hot water may 
dissolve a small but appreciable quantity of it. Copper, 
zinc, and arsenic are also metals that may be taken up 
by certain waters and that may cause serious results from 
the use of the latter. 

Of the infectious diseases, germs of typhoid fever, 
cholera and dysentery are usually carried into the system 



WATER. 155 

by the drinking-water, while the same is often true of 
yellow fever, scarlet fever, diphtheria and kindred dis- 
eases, and possibly of malaria. 1 But, as with the impuri- 
ties causing non-infectious disturbances, water containing 
disease germs may sometimes be used for a long time by 
those accustomed to it without the development of the 
specific malady, and it may only be after the system is 
weakened by excesses or other predisposing conditions 
that the disease manifests itself; or it may happen that 
only strangers and non-acclimated inhabitants incur the 
disease. It has been suggested that this immunity is 
probably brought about by the very gradual introduction 
into the body of the disease germs and their poisons, so 
that old residents are not susceptible to the small numbers 
or quantities of these which are sufficient to give rise to 
the symptoms of the particular diseases in new-comers. 

Many inslances have been recorded which practically 
prove the transmissibility of infectious diseases by means 
of drinking-water, and of these reference may be made 
to the epidemics of typhoid fever at Lausen 2 in Switzer- 
land, and at Plymouth, Pa.; 3 of malaria on board the 
transport ship "Argo; JM and of cholera in London. 5 

1 For a long time the belief that malaria is very frequently, if not most often, 
transmitted by the drinking water has been held by many sanitarians, and there 
has seemed to be much circumstantial evidence to substantiate this opinion. 
Comparatively recently, however, careful scientific investigation has apparently 
proved that this disease can be and very often is due to direct inoculation by at 
least one species of mosquito, which acts as an intermediary host in the life cycle 
or development of the malarial organism (Plasmodium malariae), and some have 
gone so far as to say that the disease is probably only transmitted in this way. 
While admitting the force of these arguments and evidence, and accepting the 
mosquito theory, the writer, for the present at least, is not convinced that the 
drinking-water cannot and does not also often serve as a means of transmitting 
the disease. 

2 Pepper's System of Medicine, vol. i., p. 250. 

3 Rohe's Text-book of Hygiene, 2d edition, p. 63. 

4 Parkes' Hygiene, 8th edition, p. 64, and Robe, p. 60. 5 Roh6, p. 64. 



156 A MANUAL OF HYGIENE AND SANITATION. 

The writer himself had an opportunity of investigating 
an epidemic of typhoid fever in a small village in North 
Carolina. 1 In this there were only four or five in about 
sixty cases which were not undoubtedly due to the con- 
tamination of the subsoil-water by the infected excreta 
from the first case; and of four of the exceptions (which 
were in one family), the first was in all probability iufected 
while in attendance upon sick neighbors, and the other 
three by direct contagion. It was also shown that with 
the exception of these four the cases all developed directly 
along the lines of natural drainage leading from the resi- 
dence of the original case — a boy, who came to the village 
sick with the disease — and that the latest cases to develop 
were those most remote from the starting-point of the in- 
fection. 

Moreover, in most large cities of this and other coun- 
tries the typhoid fever death-rate is accepted as the direct 
index of the character of the water-supply, and it seems 
to be a fact almost without , exception that any marked 
improvement in the latter will be followed by an imme- 
diate and positive reduction in the former. The same 
may also be said to hold good in regard to diarrhceal dis- 
eases, while in eastern North Carolina there has been a very 
marked reduction in the prevalence of so-called malarial 
fevers as a result of the efforts of the State Board of 
Health to persuade the people to substitute rain-water or 
deep well-water for the subsoil-water which was almost 
universally used a few years ago. 

The ova of certain parasites, such as tapeworms or 
round-worms, may often be taken into the system with 
the drinkiug- water, and these upon developing may cause 



University Medical Magazine, May, 1892. 



WATER. 157 

serious disturbances that may require more than the slight 
attention usually given to them. Any attack of convul- 
sions in a child or other manifestation of severe reflex 
action should lead to the inquiry as to whether these 
parasites may not be present and whether the water- 
supply has not been the source of invasion. 

Regarding the foregoing remarks, Parkes makes the 
following statements : " 1. An epidemic of diarrhoea in a 
community is almost always owing to either impure air, 
impure water or bad food. If it affects a number of 
persons suddenly, it is probably owing to one of the last 
two causes, and if it extends over many families, almost ' 
certainly to water. But as the cause of the impurity may 
be transient, it is not easy to find experimental proof. 2. 
Diarrhoea or dysentery constantly affecting a community, 
or returning periodically at certain times of the year, is 
far more likely to be produced by bad water than by any 
other cause. 3. A very sudden and localized outbreak 
of typhoid fever or cholera is almost certainly owing to 
the introduction of the poison by water. 4. The same fact 
holds good in malarial fevers, and, especially if the cases 
are very grave, a possible introduction by water should 
be inquired into. 5. The introduction of the ova of cer- 
tain entozoa by means of water is proved in some places, 
probable in others. 6. Although it is not at present pos- 
sible to assign to every impurity in water its exact share 
in the production of disease, or to prove the precise in- 
fluence on public health of water which is not extremely 
impure, it appears certain that the health of a community 
always improves when an abundant and pure water-supply 
is given; and, apart from this actual evidence, we are 
entitled to conclude from other considerations that abun- 
dant and good water is a prime sanitary necessity. " The 



158 A MANUAL OF HYGIENE AND SANITATION. 



statistics already given and those to come in later pages 
are confirmatory of the correctness of this last assertion, 
aud sanitary authorities now realize that, in addition to 
the mortality from typhoid fever, the main cause of an 
increase in the death-rate of diarrhoeal diseases is more 
often to be fairly attributed to a bad water-supply than 
to improper food or untoward temperatures. Even with 
respect to cholera infantum (which is generally supposed 
to be principally due to the influence of excessive heat 
upon the infant and its food), a number of epidemics 
show a closer relation to impure water-supply than to 
temperature changes. 

The Purification of Water. Impurities in water may 
be either solid matters in suspension or dissolved sub- 
stances, and- may be organic or inorganic. Any turbidity 
is due to solid particles, and water free from these is clear, 
though it may have a color more or less deep from dis- 
solved matters. But a clear water may contain such 
solid bodies as bacteria, ova of parasites, etc., which are 
too minute to be seen with the naked eye. Whether 
harmful or not, all impurities should be removed in so 
far as is possible from all supplies of drinking-water. 
This may be done to a considerable extent with large 
volumes of water before the distribution to consumers, 
and should always be attended to by the latter if the 
water is not already clean and within the limits of safety 
when they receive it. In fact, a large city at the present 
time can scarcely have a more important subject for con- 
sideration than that of obtaining the purest possible water- 
supply for its people. There is always a tendency among 
many to allow matters to continue as they are or as they 
have been in the past, and a decided objection by others 
to incurring additional expense for what may seem to them 



WATER. 159 

only aesthetic reasons; bat, no matter what may be the 
cost of providing a reasonable supply of pure water for 
any large city's personal and domestic uses, a very little 
consideration will show tliat such expenditure is true 
economy from solely a financial point of view, even 
though we ignore the misery and sorrow of the sickness 
and deaths that are due to the use of a polluted water. 

As has been stated by the excellent authority quoted 
above, " the health of a community always improves 
when an abundant aad pure water-supply is given." 
" The death of 3400 persons from cholera followed the 
temporary supply of unfiltered water by the East London 
Water Company in 1866, while the rest of London re- 
mained nearly free from the disease," and in 1892 " Ham- 
burg lost 8605 citizens from the same disease alone," 
regarding which " the health authorities found that the 
principal cause of this epidemic was the polluted water- 
supply." 1 

Again, after the scourge of typhoid fever in Plymouth, 
Pennsylvania, in 1885, when there were 1104 cases and 
114 deaths within a few weeks in a population of 8000 
as a result of the pollution of the water-supply by a single 
person, great care was taken to determine the exact cost of 
the " visitation," as some would term it. It was found 
that the actual expenditure for the care of the sick 
was $67,100.17; for loss of wages by those recovering, 
$30,020.08; a total of $97,120.25, to which should be 
added a number of times the $18,419.52 that those who 
died were earning per aunum when taken sick. How 
much cheaper in comparison would a protecting filter- 
plant have been ! But overlooking special epidemics, 

1 Hazen : The Filtration of Public Water Supplies, 1895. 



160 A MANUAL OF HYGIENE AND SANITATION. 

and considering the average annual typhoid death-rates 
of our cities, we find that experience both here and abroad 
shows that with a pare water-supply a maximum death- 
rate from this disease is 25 per 100,000, and that any 
city may reasonably expect to secure even a lower rate by 
observing proper precautions. And yet only eight cities 
of over 50,000 population whose mortality returns were 
given in the United States Census Reports of 1 890 had 
so low a figure. On the other hand, there were five cities 
of over (and two of less than) 50,000 that had 100 or more 
deaths per 100,000, all seven using unfiltered river-water. 
The remaining forty-one of those above 50,000 had rates 
varying from 26 to 98. Counting each death as a loss 
to the community of $5000 — not an excessive estimate 
according to the finding of courts in cases of death by 
accident, and since most typhoid cases occur during the 
working age of from fifteen to fifty years — " the saving 
due to filtration " on the unnecessary deaths from typhoid 
fever " would have paid for the entire cost of filters in 
the first year they were in use " in the first seven of these 
cities; i( in sixteen others, with an aggregate population of 
3,717,560, filtration would have paid for itself in two 
years or less," and in "eighteen others with an aggregate 
of 3,238,617, filtration would have saved seven or more 
lives per 100,000 annually, and would have more than 
paid for the interest and cost of operating the filters." 1 

Lawrence, Mass., with a population of 44,654 in 1890, 
built a filter at a cost of $67,000, and saved enough lives, 
at $5000 per head, to pay for it within the first four 
months that it was in use, and had a reduction of almost 
60 per cent, in the typhoid death-rate within a year. 

1 Hazen : The Filtration of Public Water Supplies. 



WATER. 161 

In Chicago, when the similarly estimated loss from 
typhoid deaths in the city and suburbs amounted to over 
$10,000,000 in 1891, the abandoning of a shore inlet near 
the mouth of the sewage polluted Chicago River in 1892 
resulted in a reduction of 60 per cent, in the typhoid 
mortality during the following year. Albany, N. Y., 
is also said to have reduced the death-rate from this dis- 
ease 70 per cent, since the installation of its filter plant. 

But it is only when oue realizes that an increase in the 
mortality from any cause of only one in one thousand of 
population means one thousand additional deaths per annum 
ia a city of a million, that he can appreciate the meaning 
and the loss in capitalization to the municipality of the 
exceedingly high typhoid mortality that obtains in some 
of our large cities. At the valuation of $5000 per capita, 
and considering only the excess above the maximum 
typhoid mortality of a pure-water city, this death loss in 
one city alone for several years has amounted to upward 
of $500,000 annually. Nor must it be forgotten that 
these figures do not include the cost of medical attention 
and nursing for the thousands who were sick, nor the loss 
of time and employment by those who recovered, nor do 
they consider the financial loss due to sickness and deaths 
from diseases other than typhoid fever that may be fairly 
credited to polluted water-supplies. Can anyone doubt 
where true municipal economy lies, and is there not 
abundant opportunity for sanitary education and work 
in this direction alone for many years to come? 

Purification before distribution may be by either or all 
of three methods : subsidence, chemical treatment, and 
filtration. 

The first method consists in allowing the water to stand 
in large reservoirs until the greater part of the suspended 

11 



162 A MANUAL OF HYGIENE AND SANITATION. 

matters have fallen to the bottom. If sufficient time be 
given, much of the organic matter, whether solid or dis- 
solved, will be decomposed or reduced to simpler com- 
pounds by the action of the sunlight, oxygen, animalcule, 
saprophytes, etc. Most of the bacteria also, especially 
the pathogenic species, will disappear either by sedimen- 
tation or by death from lack of favorable conditions. 
Consequently, a water originally quite impure may be 
much improved by this method alone, while if it is used 
in conjunction with and preliminary to filtration it will 
be additionally advantageous, in that it reduces the cost 
of the latter by lessening the frequency and expense of 
cleaning the filters. 

What the capacity of the reservoirs and the time of 
storage should be, depend on circumstances. If it is the 
only method of purification employed, and especially if 
the water is very foul, the longer the time of storage the 
better. Again, if the source of supply is variable in out- 
put or if it is liable to excessive pollution for limited 
periods, the capacity should be such, if possible, that 
water need not be collected during the emergency. On 
the other hand, if the water is to be subsequently filtered, 
the capacity of the reservoirs and time of storage need not 
be so great. Most German authorities on filtration hold 
that sedimentation for twenty-four hours or even less is 
sufficient, most of the solid matters being precipitated 
within that time, if at all, and the filters being relied 
upon to remove the remainder, especially the finer par- 
ticles and the bacteria. The English practice is to store 
the water for a longer time, though local causes related 
to the source of supply are the reason for this. Thus the 
Lea and Thames, from which the London companies take 
much of their water, are subject to extra pollution in 



WATER. Ig3 

times of flood, which are usually of short duration, and a 
sufficient reserve for such periods is of obvious value. 

All storage reservoirs should, of course, be kept free 
from extraneous contamination and should be cleaned 
from time to time. This necessitates an arrangement in 
pairs or groups, or a partitioning of large reservoirs, so 
that one part may be cleansed without putting the rest 
out of service. Weeds should be destroyed, as they some- 
times give a bad taste to the water. The water may also 
have a bad taste or odor from algae and other species of 
minute plants, which especially favor a pure water ex- 
posed to sunshine. They are not known to be harmful, 
but it may be necessary to cover the reservoirs to get rid 
of them aud their unpleasant properties. 

Where a water is very hard or contains an excess of 
mineral matter it is frequently of advantage to treat it 
chemically. If the hardness is due to the bicarbonate of 
calcium in excess it may be removed by the addition of 
a solution of calcium hydrate to the water, the insoluble 
carbonate of calcium being formed and precipitated. The 
change is represented by the equation: 

CaOC0 2 C0 2 + Ca(HO) 2 = 2CaC0 3 + H 2 0. 

Clark's process, based on this reaction, is as follows: 
About fourteen or fifteen hundred-weight of lime is 
allowed to each million gallons of water, the actual 
quantity of lime depending on the amount of bicarbonate 
in the water. The lime is slaked in a tank into which 
the water to be treated flows; the mixture is well stirred 
and then allowed to stand for twelve hours, when the 
supernatant water is drawn off, the tank cleaned and the 
process repeated. The water is not only softened in this 
way, but the precipitate usually carries down with it much 



164 A MANUAL OF HYGIENE AND SANITATION. 

of the solid impurities and organic matters in the water. 
This process is extensively used in England, where much 
of the available water is derived from the underlying chalk- 
beds, and thus has a superabundance of the bicarbonate; 
but the writer is unaware that it finds any general appli- 
cation in this country, though it might be an advisable 
method of treatment in certain of our limestone districts. 

If alum (sulphate of alumina) be added to an impure 
water, a decomposition of the salt occurs, the acid portion 
combining with the bases in the water and forming a floc- 
culent precipitate of insoluble basic sulphates and alum- 
inum hydrate, which entangles iu it and carries down 
the suspended impurities in the water, beside removing 
much of the dissolved organic and coloring matters. 
Moreover, careful experiments have shown that the addi- 
tion of only about one grain of alum per gallon, followed 
by thorough agitation and subsequent settling for twenty- 
four hours, will almost invariably give a water free from 
germs and one that will tend to remain sterile for a con- 
siderable time; this possibly being due to the removal of 
the food-supply of the bacteria. 1 

The use of alum is especially advantageous when a water 
contains a very fine silt or the like in suspension, and 
which is not removed by subsidence, even after a con- 
siderable time. It is also to be used in conjunction with 
or preliminary to mechanical filtration, which latter, at 
the usual rate of operation, is oftentimes practically de- 
pendent upon alum for the furnishing of a safe water. 
Comparatively little alum is needed, even with a very 
dirty water — usually not more than one, or at most two, 
grains per gallon, and if the supply is practically adjusted 

1 V. and A. Babes: Centralblatt fur Bakteriologie und Parasitenkunde, 1892 ) 
vol. xii., No. 45. 



WATER. 165 

to the condition of the water, as it should be, the extremely 
minute quantity of free alum that may sometimes pass 
through the filters is harmless and unimportant. 

Should the water be lacking in sufficient bases, which, 
however, is extremely improbable, it might contain when 
filtered a very little free acid, which can be readily neu- 
tralized by the addition of a correspondingly small quan- 
tity of soda, the resulting salt affecting neither the health- 
fulness nor the palatability of the water. It has been 
suggested that the alum be first decomposed by the addi- 
tion of soda, then washed free from the resulting sodium 
sulphate and the flocculent hydrate of alumina added 
to the water, thus avoiding the chance of there being 
either free alum or acid in the cleared water ; but experi- 
ments show that the results are not as good as when alum 
alone is used. 

Regarding the danger from the use of water purified 
by the addition of alum, Hazen says: "Although alum 
in large quantities is undoubtedly injurious to health, it is 
neither a violent nor a cumulative poison; and the propo- 
sition that one part of alumina in a million parts of water 
is injurious to health must be regarded as conjecture rather 
than as a matter of proof or even of probability." 

The Anderson process, which consists in the agitation 
of the water with metallic iron before filtration, has been 
employed at Antwerp and elsewhere; but it is not clear 
that, with large quantities of water, better result's are 
obtained than by simple filtration. The idea is that 
some of the iron is converted into soluble ferrous car- 
bonate, which then oxidizes to insoluble ferric hydrate 
and carries down with it the suspended and many dis- 
solved impurities, and thus facilitates their removal by 
sedimentation and filtration. The difficulty in using this 



— 



166 A MANUAL OF HYGIENE AND SANITATION, 

process on a large scale seems to be that the carbonate is 
not formed quickly enough, and also that too much of 
the iron may remain iu solution even after nitration. 

Filtration. For the purification of large quantities of 
water, such as are needed for great cities, there can be no 
question that sand nitration is, in the majority of cases, 
the most available, satisfactory and efficient method, 
though it may often be advantageously preceded by sedi- 
mentation or by chemical treatment, as already described. 
The former especially, by removing much of the suspended 
matter, will prolong the use of the niters between clean- 
ings and thus materially lessen the cost of maintenance; 
while the latter may greatly improve the chemical quality 
of the filtered water. 

Municipal filters of the type to be described are as yet 
not widely nor sufficiently well known in this country, but 
they have been used abroad with increasingly good results 
for upward of half a century, and they now furnish the 
daily supply of water to more than twenty millions of 
people. However, we may take credit in the knowledge 
that the most thorough and scientific investigation of their 
action and efficiency has been made on this side of the 
Atlantic, under the auspices of the Massachusetts State 
Board of Health, and that it is to this body that we are 
indebted for much of the positive information that we 
now have concerning them. 

The limitations of this work do not permit a full dis- 
cussion of the principles or merits of such filters, but the 
following details are given that the reader may appreciate 
the simplicity of their construction and the efficiency of 
their work. Those desiring more extended information 
are referred to the Massachusetts reports that discuss this 
subject, and to the excellent work of Dr. Hazen, already 



WATER. 



167 



mentioned, 1 from which many of the accompanying state- 
ments and illustrations have been taken. 

Almost without exception these filters now consist of a 
layer of clean sand of a certain degree of fineness spread 
upon a layer of gravel in a carefully prepared basin, the 
whole being underdrained and proper arrangements made 
for the controlling of the depth of water upon the surface, 
rate of flow of the filtrate, cleaning of filters, etc. (Fig. 
29.) Such filters act primarily as strainers to remove the 



Fig. 29. 



Supply to Filters 




By Pass 



IHI' jiflntake 



- Outlet Pipes 



Inlet Pipes — 



Sedimentation 

Blow Off 



Basin 




Supply to Filters 

Plan of filter-beds at Albany, N. Y. 



solid impurities from the water, but their efficiency is 
much increased by the sediment itself that is retained 
upon the surface of the sand which forms a filter much 
finer than the latter and is capable of mechanically 
preventing the passage of most of the bacteria always 
present in a surface-water. Moreover, this removal of the 
bacteria is often largely due to the organisms themselves 

i Filtration of Public Water Supplies. 






168 A MANUAL OF HYGIENE AND SANITATION. 

in the sediment-layer, because by forming a felt-like 
growth therein they not only increase the fineness of the 
strainer, but by acting as saprophytes they decompose 
much of the organic matter and even kill the patho- 
genic bacteria. However, it now seems probable that 
for continuous filters the action is mainly mechanical, 
consisting in the removal of suspended matters and bac- 
teria and but slightly affecting the dissolved organic 
matters. On the other hand, in intermittent filtration, 
where the conditions more nearly resemble those in the 
natural soil and where the filters are periodically aerated, 
the straining action is less perfect on account of the 

Fig. 30. 




' " **^JI u AM. BANK NOTE CO, N.Y. 

General arrangement of filter-plant. (Hazen.) 

greater rate of filtration necessary, but the nitrification 
and destruction of organic matter due to the action of 
the saprophytes and oxygen are greater. Intermittent 
filters, therefore, will probably prove to be the better 
for the purification of sewage or a very impure water, 
though usually their efficiency in removing bacteria seems 
to be inferior to that of continuous filters. 

The location of the filter-beds with respect to the source 
of supply and the storage reservoirs will depend largely 
on local conditions, economy in cost of pumping, etc. 
Settling tanks are almost essential where the water to be 
filtered is very turbid, even if only at intervals. Reference 



WATER. 



169 



has already been made to the difference of opinion 
between English and Continental authorities regarding 
the size of these settling basins. As the filtration does 
not remove hardness due to dissolved minerals, it may 
also be advisable to use the Clark process previous to 
sedimentation and filtration. Part of the color due to 
peat or vegetable matters is removed by ordinary filtra- 
tion, and still more may sometimes be taken away by the 
previous addition of alum, but such preliminary treatment 
is unusual. Where the water comes from a lake or from 
a river with a slow current, settling basins are, of course, 
unnecessary. 

Fig. 31. 







- ^^X^^/Mxs^^^>^&& 



2 
-rJ-i-r 



6 Meters 



5 10 15 20 Feet 

Regulation of inflow used at Hamburg. (Hazen.) 



Iuasnmch as it is needful to govern the depth of the 
water upon the filter-beds, and to prevent the disturbance 
of the sand and sediment layer by the force of the enter- 
ing current, some method of regulating the inflow is 
required. The accompanying illustration shows a com- 
paratively simple arrangement for this purpose. (Fig. 31.) 

The total area of the filter-beds will depend upon the 
amount of water needed, the rate of filtration, and the 
proportion of area out of use while being cleaned. The 



170 A MANUAL OF HYGIENE AND SANITATION. 



total area is to be divided into beds, varying in number 
according to circumstances, so that one or more of these 
beds may be cleaned while the rest are in use. Large 



Fig. 32. 




Interior of a covered filter ready for use. 
Fig. 33. • 







Sectional plan of a covered filter. 

beds decrease the cost per acre on account of less masonry, 
etc., being needed, but it may be more difficult to main- 
tain an even action over the larger areas. This latter 



WATER. 171 

point is, however, largely governed by the size and 
arrangement of the underdrains. 

The walls and bottoms of filter-beds should be made 
water-tight, that there may be no waste of the filtered 
water on the one hand, nor any ingress of foul soil-water 
on the other. The form of the filter-bed is immaterial, 
provided evenness of work over the whole area is not im- 
paired. Where the mean January temperature is below 
the freezing point the beds should be covered, as the 
formation of ice upon them seriously impairs their 
efficiency, and as, moreover, a number of epidemics of 
typhoid fever and certain intestinal diseases seem to be 
directly traceable to ice-formation. This may have been 
on account of the overtaxing of the filters through in- 
creased difficulty in working, or because the sedimenta- 
tion layer and the saud were disturbed in the removal of 
the ice. 

As already stated, the materials used practically every- 
where are clean saud and gravel, and the sharper the 
sand-grains the better. At the Lawrence Experiment 
Station of the Massachusetts State Board of Health " the 
size of a sand-grain is uniformly taken as the diameter of 
a sphere of equal volume, regardless of its shape. " More- 
over, as it is " the finest portion which mainly determines 
the character of sand for filtration/' the effective size is 
taken to be " the size of a grain such that 10 per cent, by 
weight of the particles are smaller and 90 per cent, are 
larger than itself. 7 ' As uniformity of grain is also im- 
portant, the uniformity coefficient is " the ratio of the size 
of grain which has 60 per cent, of the sample finer than 
itself to the size which has 10 per cent, finer than itself." 
Obviously, the velocity of water through a layer of sand 
will depend upon the effective size of the sand, the 



172 ^ MANUAL OF HYGIENE AND SANITATION. 

thickness of the layer through which the water passes, and 
the loss of head due to the f rictional resistance of the sand. 
A rise of temperature causes a progressive increase in 
velocity. 

The effective sizes of sand-grain in use in most of the 
foreign filters average from 0.31 to 0.40 mm. In gen- 
eral, it may be said that the finer the sand the better is 
the quality of the normal filtrate and the less the danger 
of an unsafe effluent in case the sediment layer on top of 
the sand is broken; but, on the other hand, cost of filtra- 
tion increases with the smallness of sand-grain, since the 
filters must be cleaned oftener and fine sands are harder 
to wash, as well as because the velocity of flow is slower 
through fine sands. All things considered, the best results 
will probably be obtained with a sand having a uniformity 
coefficient of not more than 3 — the lower the better — and 
an effective size of from 0.20 to 0.35 mm., the latter 
depending largely upon the character and clearness of 
the water to be filtered. 

The thickness of the sand-layer should be such that it 
may be scraped a number of times before becoming so 
thin as to require replacing. The German Imperial Board 
of Health requires a thickness of at least twelve inches 
after the last scraping; while the original thickness should 
be from twenty-four to forty- eight inches, the thicker the 
better, provided the cost of the filter be not made too 
great and the rate of filtration be not too much dimin- 
ished. The sand should be of the same degree of fineness 
throughout. 

As for the gravel beneath the sand, there is no reason 
why it should be of excessive thickness. A depth of one 
foot is probably sufficient, provided the stones are of vary- 
ing size, so arranged that the sand above will not work 



WATER. 173 

into and through the interstices, and that the water may 
freely enter the underdrains at low velocity. The loss of 
head in water flowing through a thin layer of gravel prop- 
erly placed is comparatively slight. Foreign filters do 
have a gravel layer of two feet or more in thickness, as a 
rule, but careful experiments at Lawrence, Mass., show 
that this depth is entirely unnecessary, provided that the 
gravel is properly laid as indicated, and that the under- 
drains are not too far apart. 

The underdrains should be of such size and so con- 
structed that the frictional resistance which they offer to 
the flow of the water is only a small percentage of that of 
the clean sand, and that the rate of filtration is the same 
over the whole area of the filter. There is usually a main 
drain along the middle of the filter floor with smaller par- 
allel lateral drains leading into it at regular intervals. 
The drains may be made of brick with open joints, or, 
for the laterals, of tile, which is usually cheaper. Care 
must always be had that the openings are sufficient in 
number and size to admit the water freely. 

The area drained should vary from about 300 square 
feet for a four-inch lateral drain to 4400 square feet for 
a twelve-inch main, the velocity of flow in these being 
respectively 0.30 and 0.51 foot per second; while larger 
drains should have a cross-section of at least one-six- 
thousandth of the drained area. The European custom 
of ventilating drains by means of pipes passing up through 
the sand and water above is not to be commended, since 
such ventilation apparatus is unnecessary, increases the 
cost of the filters, and, what is worse, may allow im- 
purities to contaminate the filtered water in the drain. 

Recently it has been suggested that the filter-beds be 
constructed directly over the storage reservoirs for the 



174 A MANUAL OF HYGIENE AND SANITATION. 



filtered water, the beds being supported on suitable steel 
columns resting on concrete foundations in the bottom of 
the reservoirs. The bottom layer of the filter, composed 
of gravel or broken stone, would rest on steel tubes or 
bars several feet above the level of the water in the reser- 
voir, thus allowing the filtrate to be aerated as it falls 
through the intervening space. Theoretically, it would 
seem that the plan is a good one, and actual results indi- 
cate that it practically is so. Some of the advantages are 
the absence of underd rains and loss of the resistance factor 



Fig. 34. 







12 3 

^7 



5 6 7 8 Meters 

I I i' I I I 'l I 
15 20 25 Feet 

Simplest form of regulation. Stralau filters at Berlin. (Hazen.) 



10 



due to them, the aeration of the filtrate as indicated, and 
also the practically continuous aeration of the filter-bed 
itself, thus enabling the saprophytic bacteria in the upper 
layers to carry on their work of oxidizing and nitrifying 
the organic impurities of the water. One serious objec- 
tion to such a filter is that an accidental overflow would 
contaminate at once all the filtered water in the storage 
reservoir. 

The depth of water upon the filter-beds must be regu- 
lated according to the rate of flow desired, the thickness 



WATER. 175 

and resistance of the sand, etc. (Fig. 34.) Although it has 
been the custom to keep the depth in excess of the loss of 
head, this is not essential. On foreign filters the usual 
depth is from thirty six to fifty-two inches, though less than 
this might suffice in many instances. The necessity of 
regulating the inflow and of maintaining a constant level 
must not be overlooked if uniform results are desired. 

Summarizing the preceding statements, the rate of filtra- 
tion and loss of head will depend upon the depth of water 
on the filters, the thickness of the sand-layer, size of sand- 
grains, resistance of underdrains, temperature, etc., and 
all these will likewise affect both the cost and the efficiency 
of the filtration. 

Two million gallons per day will probably be a safe rate 
of filtration to maintain continuously, though with a clear 
water or in emergencies a rate one-half greater will very 
likely not materially alter the quality of the filtered water 
or increase the risk. But in general as the rate increases 
the efficiency decreases. Where the filters are constructed 
above the storage reservoirs in the manner described, it 
is claimed that much larger quantities of water may be 
filtered in the given time with equally good results. If 
this be so, it is probably due to the increased saprophytic 
and oxidizing action resulting from the continuous aera- 
tion of the filter. 

As the sediment accumulates and deepens upon the sur- 
face of the sand the rate of flow necessarily diminishes 
and it becomes necessary after a time to remove the de- 
posit. This is done by carefully scraping off the top layer 
of the sand to the depth of from one-half to one and one- 
half inches, repeating the scraping as often as may be 
necessary until the thickness of sand above the under- 
lying gravel is near the permissible minimum. Then 



176 A- MANUAL OF HYGIENE AND SANITATION. 

the sand which has been removed, and which has mean- 
while been thoroughly washed by a stream of the filtered 
water, driven, if necessary, by a force-pump, is carefully 
replaced, packed and levelled upon the beds. These do 
not again attain their greatest efficiency until a certain 
amount of sediment from the water has once more col- 
lected upon them, and it is, therefore, not wise to use the 
filtered water for some time after the cleaning and until 
bacteriological tests show that the maximum purification 
is being attained. 

An essential in the management of all large filters is 
the daily bacteriological and chemical examination of both 
the filtered and unfiltered water. This not only serves to 
give warning of any accident to the filter, but the best test 
of the efficiency of a sand-filter is the proportion of bacteria 
which it takes from the unfiltered water. Unless a filter 
is holding back from 98 to 99 per cent, or more of the 
bacteria, it needs close inspection, although it must be 
remembered that it is more difficult to get good results 
with a badly polluted water than with one that is compara- 
tively pure. 

Domestic Purification of Water. Boiling destroys 
living organisms and disease germs; it also drives off the 
carbonic acid and other gases of the water and causes the 
precipitation of many mineral substances held in solution 
by these gases. This is especially the case, as has been 
stated, where the water is hard from the preseuce of cal- 
cium bicarbonate in excess; but iron is also often thrown 
down by boiling. If the water contains a very fine sedi- 
ment, not removed by settling or filtration, it may be 
advantageous to add a little alum and chalk to produce 
the flocculent precipitate already described. Potassium 
permanganate has little effect in purifying a foul water. 



WATER. 177 

Agitation with iron-filings may do a little good by favor- 
ing oxidation of organic matters. Tannin is thought to 
destroy micro-organisms, and a harmful water may some- 
times be made usable by boiling with tea-leaves or other 
astringents. Citric acid is said to destroy algae. Aera- 
tion and agitation improve a water after distillation or 
boiling by restoring oxygen and also by oxidizing organic 
matters. Remember that boiled water is prone to take 
up gases of any kind, whether impure and offensive or 
otherwise. Organic matters are got rid of by boiling, 
exposure to air, agitation, addition of alum, astringents, 
charcoal, etc. ; bicarbonate of lime, by boiling or by add- 
ing caustic or slaked lime or a little soda; iron, by boil- 
ing and by adding lime-water. Calcium and magnesium 
sulphate and chloride cannot readily be removed. Some 
plants help to purify by means of the oxygen which they 
give to the water. 

Distillation gives, of course, a water free from harmful 
impurities, but it has lost its gases and is improved in 
palatability by aeration or by being charged with carbonic- 
acid gas. Stills for domestic use, capable of supplying an 
abundance of water for drinking and cooking purposes, 
can now be purchased at moderate cost. The main 
objection to distillation in the household is that the 
process is somewhat slow and tedious. 

Comparatively recently an apparatus has been invented 
and introduced which furnishes a boiled water, free from 
disease germs, yet unchanged in taste by the boiling, and 
at nearly the same temperature as the water entering the 
apparatus. This is the Forbes (formerly the Waterhouse- 
Forbes) sterilizer. The principles involved in its con- 
struction and operation are that only a small bulk of 
water is being boiled at any instant, that it is only boiled 

12 



178 A MANUAL OF HYGIENE AND SANITATION. 

for a very short time, thus preventing the loss of the 
original gases and taste, that all disease germs are killed 
by the boiling, that it is impossible for any water which 
has not been boiled to pass through the apparatus, and 
that the heat of the boiled water is used to warm the 

Fig. 35. 





Diagrammatic representation of the principle of the Forbes sterilizer. 



unboiled water (thus economizing fuel) at the same time 
that the latter is made to cool the former. 

Reference to the diagram (Fig. 35) shows that the water 
can rise no higher than the level X until it "boils over''' 
through the spout a into the top of the receiver 6. The 
interchange of heat takes place through the diaphragm c, 



WATER. 179 

which in the apparatus itself is very thin and corrugated, 
so as to expose a large surface to the water on the two 
sides of it. 

This apparatus is furnished in a suitable size for house- 
hold use, but is also made on a large scale and in a con- 
venient form for transportation, and the latter has been 
adopted by the United States army as being " superior to 
all niters or other water sterilizers submitted for trial/' 
and as being u well adapted for the abundant supply of 
sterile water to troops in the field." The Board of 
Medical Officers appointed to consider the niters and 
other apparatus of the kind submitted made the follow- 
ing report: 

" The advantages of this most ingenious water steril- 
izer are : First. That water passing through it, although 
brought to the boiling-point, is maintained at this tem- 
perature for so short a time as not to be deprived of its 
natural gases, and hence not rendered unacceptable to the 
taste. Second. That all living micro-organisms . 
are destroyed by the degree of heat attained during the 
passage of the water through the apparatus. Third. It 
furnishes an abundant supply of practically sterile water, 
and may be kept in action, if necessary, for the entire 
twenty-four hours without renewing the supply of oil in 
the reservoir, and at a cost of about one-fourth of a cent 
an hour. Fourth. The water, having been slowly heated 
until it reaches temporarily the boiling-point, is afterward 
cooled to within 4.5° F. of the water entering the appar- 
atus. This is one of the important advantages possessed 
by this sterilizer. By placing the bottom of the exchange 
in a freezing mixture the temperature of the sterilized 
water as it flows from the machine may be reduced below 
40° F. Fifth. Its durability and freedom from liability 



180 A MANUAL OF BYGIENE AND SANITATION. 

to breakage. Sixth. The facility with which the appa- 
ratus may be put together and entirely taken apart ; 
only one tool, a wrench, being required for this purpose. 
Seventh. The facility with which the apparatus can be 
thoroughly cleansed. This is effected by the removal of 
the rubber cocks, thus permitting a complete flushing 
out of both exchanges. The fact that the apparatus does 
not clarify the water is also deemed of no particular im- 
portance by the Board, since this may be easily effected 
prior to its passage through the sterilizer by means of one 
or two water barrels partially filled with fine and coarse 
sand and placed at a proper height above the sterilizer. 
As a result of exhaustive experiments . . . the 
board is of the opinion that this sterilizer is superior 
to all filters or other water sterilizers submitted for trial. 
We therefore, after a careful consideration of the require- 
ments, respectfully recommend that the Forbes sterilizer 
be issued for the use of trpops serving in the field. " 

House filters are dangerous unless properly cared for, 
and may give more and worse impurities to the water than 
they take from it. What a filter takes from a water is 
left iu the filter, unless otherwise removed, and an accu- 
mulation of such impurities cannot improve the water 
passing through them. The organic matters will undergo 
decomposition and putrefaction, and will furnish a good 
culture medium for bacteria, and these, together with the 
putrefaction products, will in most cases be carried through 
the filter with and by the filtered water. A filter has no 
miraculous power to annihilate filth, and the size of a 
filter must always limit the work it can do, whatever the 
materials used. 

According to Parkes, the requisites of a good filter are: 
1. That every part shall be easily accessible for cleansing 



WATER. 



181 



or renewing the medium. 2. That the filtering medium 
shall have a sufficient purifying power and be present in 
sufficient quantity. 3. That the medium gives nothing to 
the water favoring the growth of low forms of life. 4. That 
the purifying power be reasonably lasting. 5. That there 
be nothing in the construction of the filter itself capable 
of undergoing putrefaction or of yielding metallic or other 
impurities to the water. 6. That the filtering material 
shall not clog, and that the flow of water be reasonably 
rapid; to which may be added: 7. That the filtering 
medium be such that it can be readily cleansed and ster- 



FlG. 3(3. 




Tubes of unglazed porcelain for Pasteur filter. 



ilized, or else so cheap that the removal and replenishing 
may not be neglected when necessary on account of the 
expense. 

House filters may be divided into three classes : (a) 
Those entirely disconnected from the water-supply pipes 
of the house; (6) those connected with the water-pipes, 
but intended to filter only a limited quantity, as for 
drinking, cooking, etc.; (c) those connected with the 
house service-pipe and intended to filter all the water 
used in the house. The same filtering media may be 
used in all three classes, but it will be found best in the 
first two to employ substances through which the w r ater 
passes slowly, while the latter class must necessarily filter 
the water more rapidly in order to yield a sufficient sup- 



182 ^ MANUAL OF HYGIENE AND SANITATION. 

ply. It will often be advantageous to have a settling 
tank connected with those of the first class, to prolong 
the safe use of the filter as long as possible; while the 
same object is gained in some of the second class by 
bringing the water in at the bottom, in which case there 
should be a space below the filtering medium to allow 
the suspended matters to fall away from the latter. 
Those intended to filter the whole supply of the house 

Fig. 37. 




Berkfeldt filter attached to tap. 



are generally cleansed by reversing the current and wash- 
ing the collected dirt out of the filter into a drain or 
sewer, the first water passing through the filter after this 
is done being also discarded. In such filters the quantity 
of filtering material should be sufficient to purify thor- 
oughly the water passing through it, and yet should not 
be so heavy that the reverse or washing current cannot 
lift it and separate the particles so that by their scouring 
action upon one another they may be cleansed and all the 



WATER. 



183 



lirt washed out. These niters, also, may be so arranged 
jhat a small quantity of a coagulant, like alom^ auto- 
matically added to the water before filtration. 



If this be 



Fig. 38. 





Pasteur filter with reservoir for filtered water. 

done, care must be had to supply no more of the coagu- 
lant than suitable tests show to be necessary, else the 
excess may be carried through the filter in solution. 



184 A MANUAL OF HYGIENE AND SANITATION. 






Several filters of the second class have been provided 
with self- cleansing devices to obviate opening or taking 
the filter apart as frequently as would otherwise be 
necessary. Of these one of the very best is that of the 
Columbia filter, which has a porous tube (or tubes) very 
similar to those of the Pasteur-Chamberland type. Around 
this tube is a compact mass of white quartz sand, which 
is, however, set in active motion by the opening of the 
cleansing valve and thoroughly scours the exterior of the 
filtering tube until it is entirely cleansed of the suspended 
matter which it has removed from the water. Moreover, 
as the water is received into an air-tight reservoir and 
accumulates there, when not immediately used, until the 
air-pressure in the reservoir equals the pressure from the 
street-main, the opening of the cleansing valve permits the 
compressed air to drive the filtered water back through the 
filtering tube and thus to cleanse its pores of any impuri- 
ties that may have entered them. A few moments each 
day and the turning of a valve suffices for the cleansing, 
and so effectual is it that most of the objections to tube- 
filters are eliminated. In fact, while giving a germ-free 
water, more is obtainable per day per tube with this filter, 
and there is less aunovance, loss of time and risk of 
breakage of tubes in the cleansing. 

No matter what kind of filter is used, the drinking- 
water should always be boiled in times of epidemics or 
when the water before filtration is especially impure; for, 
though the Berkfeldt, the Pasteur-Chamberland and a 
few other filters are practically bacteria proof, there 
always remains a possibility that disease germs may by 
some means pass through the medium or gain access to 
the water after it is filtered. The writer's own opinion 
is that there is a saprophytic or biologic action in most 



WATER. 185 

good filters that are regularly and frequently cleaned 
very similar to that which takes place in filter-beds on a 
large scale, and that ordinarily few, if any, bacteria pass 
through with the water; but, nevertheless, the risk should 
not be taken if there is danger of incurring disease at any 
time. 

Filters in which the material is cemented up so that it 
cannot be removed for cleaning or renewal should not be 
used. Sponge, wool, etc., are liable to decompose and give 
organic matter to the water and, moreover, cannot be 
thoroughly cleaned. Asbestos acts only as a mechanical 
filter and may allow albuminous matter and disease germs 
to pass. Asbestos-cloth may be used, however, to support 
the other filtering media in those filters where the water- 
supply enters at the bottom, and it has the advantage that 
it can be perfectly sterilized by fire. Small tap filters are 
insufficient for the work required of them and soon clog. 
Pocket filters are simply strainers, and have little oxi- 
dizing power. They may be quite useful for tourists, 
hunters, etc., but should be frequently sterilized by boil- 
ing. Ordinarily, filters should not be placed in rain-water 
cisterns, but outside, where they may be readily cleaned. 

Among the best filtering media are sand, animal char- 
coal, magnetic carbide of iron, spongy iron, etc. Unglazed 
porcelain or bisque, as is used in the Pasteur Cbamberland 
filter, is an excellent medium, and is practically germ proof, 
though some observers state that bacteria will pass through 
uncleaned filters of this material after five or six days. 
Others claim that these are not bacteria, but only the 
mycelia of certain budding fungi, with no power of repro- 
duction. The tubes of the Berkfeldt filter are made of 
diatomaceous earth, moulded into shape by powerful 
hydraulic pressure, so that the water percolates through 



186 A MANUAL OF HYGIENE AND SANITATION. 

the pores of the minute fossil shells rather than between 
them. Stone filters may be good, and resemble the 



Fig. 39. 




Glass model of Loornis-Manning filter, showing filter in. action. 

porcelain ones in action, but are apt to be slow and must 
be cleansed often. Sharp, clean sand, not too fine, has 



WATER. 



187 



fair filtering properties, as it stops most of the suspended 
matters and bacteria, beside oxidizing somewhat the dis- 



FlG. 40. 




Glass model of Loomis-Manning filter, showing material during cleansing. 

solved organic matters. It makes a good first layer for 
a filter, because it is cheap and can be easily renewed or 



188 A MANUAL OF HYGIENE AND SANITATION. 

else readily cleansed and sterilized by boiling. Crushed 
quartz is of practically the same nature. 

Animal charcoal is, when fresh, an excellent material, 
as it removes both suspended and dissolved matters, organic 
and inorganic, and even color. It acts both mechanically 
and chemically, and with a good volume of it, water may 
pass through rapidly and be well purified. But after a 
time it ceases to be effective, nor must water be left too 
long in contact with it, as it will give up organic matter 
to the water again and also phosphate of lime, the latter 
especially favoring the development of micro-organisms. 
Moreover, fresh organic matter, and possibly bacteria, are 
said to pass through it readily, though dead or decom- 
posing matter is held back and rapidly destroyed. It 
should be changed or cleansed, even when in sufficient 
bulk, three or four times a year; oftener if the water to 
be filtered is very bad. It is more efficacious than any 
other substance in removing lead from water. 

Magnetic carbide of iron is one of the best filtering 
materials, as it has considerable power in oxidizing organic 
matters, converting them into nitrates and nitrites, the 
action being greater the longer the water is in contact 
with it. It acts partly by surface condensation of oxy- 
gen; partly, perhaps, by electrolytic action. If sand be 
used as a first layer to remove solid matters so that the 
water reaches the carbide perfectly clear, and if the sand 
be frequently renewed or cleansed, the carbide need never 
be changed; but the filtration must be intermittent so 
that the carbide may be frequently aerated. Spongy iron 
has an action very similar to that of the magnetic carbide 
on organic matters and, like it, the action is the greater 
the longer the contact. It must be kept covered with 
water to prevent rusting and caking and should be 



WATER. 189 

renewed about once a year. The small amount of iron 
that the magnetic carbide and spongy iron give to the 
water may be removed by passing it through a layer of 
pyrolusite — a crude oxide of manganese. A mixture of 
pyrolusite and sand or crushed quartz makes an excellent 
filtering material. 

Ice should not be added to filtered or drinking-water, 
as freezing, even for a long time, may not kill certain 
disease germs. Prudden has kept typhoid bacilli frozen 
in ice for over three months without destroying their 
power of growth and reproduction when brought to a 
suitable temperature. The same objections do not, of 
course, pertain to artificial ice carefully made from dis- 
tilled water as to that from polluted ponds or rivers; but 
it is well to cool the water by placing it in stoppered 
bottles upon ice or in vessels surrounded by ice rather 
than by adding the ice to the water directly. 

The inadvisability of using ice-water freely as a bev- 
erage should be mentioned here, as the habit is almost 
certain to cause much harm to the digestive apparatus 
and to give origin not only to intractable dyspepsias but 
to troubles even more serious. If used at all, ice- water 
should be taken slowly and in small quantities, and as 
little as possible should be imbibed at meal-time, in order 
to prevent chilling of the stomach and consequent check- 
ing of the digestion. Its use and the liking for it is 
mainly a matter of habit, which it is hygienic wisdom to 
overcome. 

The Examination of a Drinking-water should have 
regard to its physical, bacterial and chemical properties 
as well as to a consideration of all the conditions affecting 
its source, storage and distribution. Consequently, a 
decision on the purity of water should be governed by 



190 A MANUAL OF HYGIENE AND SANITATION. 

all the available knowledge of the circumstances: whether 
it is well-water, spring-water, rain-water or river-water; 
whether it has been at any time exposed to pollution; in 
what kind of a cistern or reservoir it has been stored, etc. 

A physical examination of water considers the color, 
clearness, sediment, lustre, taste and smell. Pure water 
has a bluish tint, but most waters are grayish, greenish, 
yellow or brown. Yellow or brown waters are suspi- 
cious, as the color may be due to animal matter or sew- 
age, though vegetable matters or iron may give the same 
color. Green waters are usually harmless, the color being 
due to vegetable matters. The color is judged by allow- 
ing the sediment to settle and then siphoning or pouring 
oif the supernatant water into a tall glass vessel or tube 
to the depth of about twenty-four inches; the color is then 
compared with a similar depth of distilled water, looking 
down through both upon a white surface. 

The clearness of a water is to be estimated in the same 
way, except that the sediinent is to be shaken up with 
the water. The depth needed to obscure print of a cer- 
tain size and kind of type may be used as an index. 
Where the solid matter will not readily settle, owing to the 
minuteness and lightness of the particles, one should de- 
termine whether the use of a coagulant and nitration is 
indicated, or whether boiling will tend to precipitate the 
sediment. The sediment may be roughly judged by the 
eye as to whether it is mineral or otherwise; it should also 
be examined microscopically, for which purpose it may be 
collected by using a centrifugal apparatus or by allowing 
it to settle from the water in a conical glass and then re- 
moving it to the slide with a pipette. Mineral matters 
are recognized by their crystalline or amorphous structure 
or by micro-chemical tests; vegetable cells, portions of 






WATER. 191 

leaves, etc., by their structure and the presence of chlo- 
rophyll; animal substances, as hair, wool, epithelial and 
other cells, by their peculiar characteristics. Dark-brown, 
globular masses may come from sewage. Anything indi- 
cating that water has come from human habitation renders 
it suspicious, as it may therefore contain sewage or other 
polluting substances. Some of the larger animalculse and 
sometimes iron may be detected with the naked eye. 

The lustre is supposed to indicate the amount of aera- 
tion; it may be nil, dull, vitreous, or adamantine. It 
should not be forgotten that a very impure water may be 
clear, bright and sparkling. 

Any badly tasting water should be considered suspicious. 
Dissolved animal matters may be tasteless, but suspended 
substances give a peculiar taste, whether animal or vege- 
tal. Iron is about the only ordinary mineral that can 
be tasted in small quantities. Good water depends for 
its taste mainly upon its gases, and water free from gas 
tastes flat. 

The smell of a water, if it has any, may be brought out 
by heating gently to about 110° F., or by boiling it. 
This may make evident a fecal odor, although sulphur- 
etted hydrogen may mask this latter; in such a case the 
sulphuretted hydrogen may be removed by adding a little 
copper sulphate to the water. The odor may also be de- 
veloped by allowing the water to stand in a corked bottle 
in a warm place for a few days. 

A bacteriological analysis is almost as necessary as a 
chemical one, for purity in the one respect does not neces- 
sarily indicate purity in the other. The presence of the 
bacterium coli communis in a water, irrespective of any 

1 See J. C MacDonald's Guide to Microscopic Examination of Drinking-water. 



192 A MANUAL OF HYGIENE AND SANITATION. 

pathogenic organisms, would create a suspicion of con- 
tamination by fecal matter, as this microbe is praeticalb 
a constant occupant of the human intestinal tract. 

Water may be collected for bacteriological analysis in 
sterilized, closed bulbs blown from glass tubing. The 



Fig. 41. 




Pocket-case containing sterilized culture tubes, platinum needle, and small 
alcohol lamp, used for obtaining cultures for diagnosis, etc. 

heat used in sealing the ends creates a partial vacuum 
within the bulb, so that if the tip of one end be broken 
off beneath the surface of the water the latter is drawn up 
into the bulb, which can then be resealed and conveyed 
to the laboratory. But as some of the bacteria may mul- 
tiply rapidly in transportation and as some species may 



WATER. 193 

even destroy others, it is always best, if possible, to inocu- 
late the tubes of sterilized culture media at the place 
where the supply for examination is obtained. Or one 
may add a small quantity of the water to melted nutrient 
gelatin at the time when the samples are taken and make 
plate cultures in the manner already described. The 
number of colonies resulting therefrom will indicate 
practically the number of bacteria in the volume of 
water added to the gelatin. 

The details of some simple but fairly accurate tests and 
methods employed in the chemical analysis of drinking- 
water will be given in another chapter. Here we need 
only consider the influeuce that the substances sought for 
in the analysis have in affecting potability, and within 
what limits we may consider them as being permissible 
in drinking-water. The water should be filtered or free 
from sediment for all the tests, except in the estimation of 
nitrogen as ammonia compounds and as organic matter, 
and of the oxygen-consuming power of the water. 

The amount of total solids will vary with the source of 
the water, and much more may be present in some cases 
without risk of harm than would be safe in others; but 
usually the proportion should not exceed 50 or 60 parts 
in 100,000. Only a small portion should be volatile, and 
there should be little charring on ignition, except in the 
case of waters from peaty soils; nor should there be any 
odor on ignition, especially of ammonia compounds, as 
that would indicate an excess of animal organic matter. 
Deep well-water will probably have much more total solids 
than rain-water or clear river- water, the excess being 
mainly mineral substances dissolved from the strata 
through which the water passes. 

Even the purest waters contain a little chlorine, usually 

13 



194 ^ MANUAL OF HYGIENE AND SANITATION. 

in the form of sodium chloride; but, as the latter is a con- 
stant constituent of household slops and sewage in general, 
any excess of chlorine above the amount common to the 
water of the district, unless otherwise accounted for, will 
be decidedly suspicious and sewage contamination should 
be looked for. So, also, any sudden increase in the pro- 
portion of chlorine would very likely indicate the acces- 
sion of some new source of contamination to the water. 
Unless accounted for by the strata traversed or by the 
locality, more than three parts of chlorine in 100,000 of 
water is very suspicious. 

The presence of considerable u free ammonia" in rain- 
water is not a bad sign, as it has probably been absorbed 
from the air; but the same amount in subsoil- water, espe- 
cially if with an excess of chlorine, would indicate probable 
contamination with urine, as this latter rapidly undergoes 
ammoniacal putrefaction. In such a case there will prob- 
ably also be considerable "albuminoid ammonia," but 
much albuminoid ammonia with little free ammonia and 
chlorine generally indicates vegetable contamination. 
The writer is acquainted with a case in which, although 
the water is pure and from an unpolluted source, the 
albuminoid ammonia and chlorine are in marked excess, 
the former being altogether of vegetable origin — from a 
peaty soil — and the latter characteristic of the whole dis- 
trict, which is near the sea-coast. The free ammonia is, 
however, slight in amount. An excess of free ammonia, 
chlorine, nitrates and nitrites indicates animal contamina- 
tion, though, if the pollution be by effluvia alone, there 
may be no excess of chlorine. 1 The total ammonia in 
a usable water should not be over 0.13 or 0.15 part per 

1 Kenwood's Hygienic Laboratory, p. 49. 



WATER. 195 

1,000,000. If there is almost no " free " ammonia, the 
" albuminoid" may amount to 0.10 part per 1,000,000 
without giving cause for suspicion; likewise, if there is 
but little " albuminoid," there may be considerable " free " 
ammonia; but if the u albuminoid " exceeds 0.05 part 
per 1,000,000, the " free" must not be greater than this 
proportion. The simplest test for ammonia is by means 
of Nessler's reagent — a solution of a double iodide of 
potassium and mercury. It gives a yellow or yellowish- 
brown coloration when ammonia is present. 

Organic matters of animal origin, and, therefore, nitro- 
genous, are, during oxidation, partially converted into 
ammonium compounds, and these, by the action of cer- 
tain bacteria, may be further oxidized into nitrites and 
nitrates. " Nitrification takes place under the influence 
of microbes, the habitat of which does not extend more 
than a few yards below the surface of the soil. The 
nitrifying action is probably exerted only upon the 
ammonium which is formed from the organic matter. 
The presence of some substance capable of neutralizing 
acids is necessary to continuous action. Calcium and 
magnesium carbonates fulfil this function. Nitrates are 
the final result of this action; nitrites are present at any 
given time, only in small quantity." 1 Deep water may, 
of course, also contain nitrates taken up from strata rich 
in these salts. 

Although nitrites and nitrates are not at all harmful in 
the quantities usually found in water, and though the 
water containing them may have been thoroughly puri- 
fied by natural filtration through the soil, their presence, 
as will be seen from the above remarks, is important in 

1 Leffmann and Bevam : Examination of Water, 2d edition, p. 13. 



196 A MANUAL OF HYGIENE AND SANITATION. 

determining the character of the water. The presence of 
the slightest trace of nitrites is always suspicious, and any 
marked amount of nitrates, excepting possibly in a deep 
water, should require close investigation; the nitrates and 
nitrites together measured in terms of nitrogen should not 
exceed one part per million. 

The hardness should not be greater than that indicated 
by 20 or 30 parts of chalk in 100,000, and the more 
"temporary" in proportion to the " permanent " hard- 
ness the better. 

Phosphates, not from phosphatic strata, help to indi- 
cate sewage contamination. So, also, do sulphates, though 
these by themselves may come from harmless sources. 

It will be seen from the above statements that the 
opinion regarding any water must be based on a broad 
consideration of all the circumstances in connection with 
it, and not from the presence or absence in it of any one 
or two substances which are not in themselves harmful. 
The presence of poisonous metals above the limits of 
safety, however, would alone contraindicate the use of a 
water. For instance, there should not be more than 
one-twentieth of a grain of lead or copper, one-fourth 
grain of zinc, or one-half grain of iron to the gallon in 
any water, and the faintest trace of arsenic condemns it. 

The following table has been adapted from Parkes: 



WATER. 



197 



Peopertjes. 



Class. 



Physical. 



Microscopical. 



Chemical 
(parts per 100,000). 



I. 

Pure 

water. 



ir. 

Usable 
water. 



III. 

Suspicious 
water. 



IV. 

Dangerous 
water. 



Colorless or bluish 
tint ; transparent, 
sparkling, and well 
aerated; no sediment 
visible ; no smell ; 
taste palatable. 

Colorless or slight 
greenish tint ; trans- 
parent, sparkling, 
and well aerated; no 
suspended matter, 
or easily separated 
by coarse filtration 
or subsidence ; no 
smell ; taste palata- 
ble. 

Yellow or strong 
green color ; turbid ; 
considerable sus- 
pended matter ; no 
smell , but any 
marked taste. 



Yellow or brown 
color ; turbid, and 
not easily purified 
by coarse filtration ; 
large amount of sus- 
pended matter ; any 
marked smell or 
taste. 



Mineral matter ; 
vegetable endo- 
chrome ; large ani- 
mal forms ; no or- 
ganic debris. 



Same as for pure 
water. 



Vegetable and ani- 
mal forms, more or 
less pale or color- 
less ; organic dibris; 
fibres of clothing or 
other house refuse. 



Bacteria of any 
kind; fungi: numer- 
ous vegetable or ani 
mal forms of low 
types ; epithelia or 
other animal struc- 
tures ; evidence of 
sewage or ova of 
parasites, etc. 



Chlorine under 1.4 
Total solids under 7.14 
Ammonia under 0.007 
Nitrogen, as nitrites 

& nitrates, under 0.023 
Total hardness 8.5 

Chlorine under 4.3 
Total solids " 42.8 
Ammonia " 0.015 
Nitrogen, as nitrites 

& nitrates under 0.125 
Total hardness 17.3 



Chlorine 4 to 7 

Total solids 43 to 71 
Ammonia 0.015 to 0.023 
Nitrogen, as nitrites 

& nitrates 

0.125 to 2.47 
Total hardness 

above 17 

Chlorine above 7.14 
Total solids " 71.4 
Ammonia " 0.0225 
Nitrogen, as nitrites 

& nitrates, above 0.026 
Total hardness 

above 28 5 



CHAPTEE VI. 

FOOD. 

The use of food is necessary to build up the body- 
structure, to repair waste, and to furnish force and 
energy for the proper action of all the organs, tissues 
and parts of the body. In addition, certain substances 
are needed, not so much because they become a part of 
the tissue framework or yield kinetic energy directly, as 
that they are essential factors in the multitudinous chem- 
ical reactions and changes that are continually occurring 
within the living person. We may, accordingly, define 
a food as anything that tends to fulfil any one of these 
functions, provided it is not at the same time by nature 
harmful to the economy and that it does not produce 
physiological effects out of all proportion to its nutritive 
or metabolic activities. 

Strictly speaking, this definition might include air and 
water, as the former is necessary to supply oxygen for 
union with other foods or with the tissues themselves, 
and the latter is needed to assist in the solution and 
assimilation of food-stuffs, to maintain the fluidity of the 
body-juices and to effectively moisten the tissues, to pre- 
serve roundness of form, and to flush out and remove 
from the entire system those waste matters and excre- 
mentitious substances whose retention gives rise to the 
symptoms of certain autogenetic diseases. But they are 
not usually included in the category of foods, and, having 
already been considered, they may be passed over in this 
connection with but incidental reference here and there. 



FOOD. 199 

If we classify foods according to their chemical compo- 
sition, we may separate them into the following main 
divisions : 

1. Proteids and albuminoids. 2. Carbohydrates. 3. 
Hydrocarbons or fats, and 4. Salts, extractives, etc. 
Each group is subject to different digestive and metab- 
olic processes, and each has usually a different office 
within the body; for experience aud careful experiments 
both show that all of these different classes of food are 
needed to sustain life and maintain health for any con- 
siderable length of time, and that with them nothing else 
except air and water is absolutely necessary; although 
what are sometimes called the accessory food-stuffs and 
many pleasant volatile odors and flavors are desirable 
and advisable adjuncts to the food proper, since they 
greatly favor its reception, digestion and assimilation. 
But, though each class of food has its own special function 
in the economy of nutrition, in times of need or depriva- 
tion any one of the first three divisions may, in a way, 
supply the place of either of the other two. 

Fothergill 1 epitomizes the use of the food-principles in 
this way: u The carbohydrates are the body-fuel, the sur- 
plusage being stored as fat; the albuminoids (proteids) 
serve to repair the tissues as they wear out; the salts 
form the blood-salts; the fat helps to build up normal 
health tissues, the excess being burnt as body-fuel. That 
is the real object of food." 

While in the main correct, this is a broad statement of 
facts, and it needs some qualification. For instance, 
just as there is some wear and tear in any mechanical 
machine while in use, which must eventually be provided 
for; so in the human body with its manifold activities 

1 Manual of Dietetics, p. 5. 






200 A MANUAL OF HYGIENE AND SANITATION. 

there must be some destructive effect upon the body- 
structure and tissue framework, and it is to renew and 
replace this inevitable loss of material that a part — per- 
haps the great part — of the proteid food is taken. But 
we now also know that in addition to this simple repair 
and replacement of tissue, " the presence of nitrogenized 
structure, and its participation in the action going on 
there, is a necessary condition for the manifestation of 
any vital energy or any chemical change/ 7 and we have 
reason to believe that, entirely apart from the idea of 
repair, proteid food is essential to the development and 
maintenance of this chemical and vital activity of nitro- 
genized tissue. 

Confirming this, Pettenkofer and Voigt have shown 
that the absorption of oxygen is largely determined by 
the nitrogenous substances composing the tissues of the 
body, and that it is proportional to their size and vigor. 
Moreover, it is known that proteids may be, in part, 
converted into fat and possibly into other oxidizable sub- 
stances, and thus become a source of body-heat and energy. 

So, also, with the fats and carbohydrates. While they 
are not immediately nor entirely interconvertible, and 
while neither class may be permanently excluded from 
the diet, yet in emergency either may apparently fully 
supplant and substitute the other for a time, and we can- 
not yet say exactly how similar or dissimilar their service 
within the body is. 

However, while FothergilPs epitome needs this emen- 
dation, known facts make it comparatively easy to gain 
a fair idea of the differences and functions of the proxi- 
mate food principles, to which end some help will prob- 
ably be given by the following table: 1 

1 Notter and Firth : Treatise on Hygiene, p. 257. 



FOOD. 



201 



Nitrogenous Substances. 
1. Proteids. 
All substances containing nitro- 
gen of a composition identical 
with, or nearly that of albumin ; 
proportion of N to C being nearly 
as 2 to 7 or 4 to 14. 



1 (a). Substances containing a 
larger proportion of nitrogen are 
apparently less nutritious. 

Proportion of N to C about 2 to 
b l / 2 or 4 to 11. 

(b). Extractive matters, such as 
are contained in the juice of the 
flesh. 



Non-nitrogenous Substances. 

2. Fats {or Hydrocarbons). 

Substances containing no nitro- 
gen, but made up of carbon, hydro- 
gen, and oxygen ; the proportion 
of oxygen being less than sufficient 
to convert all the hydrogen into 
water. 

Proportion of unoxidized H to 
C, about 1 to 7. 

3. Carbohydrates. 

Substances containing no nitro- 
gen, but made up of carbon, hydro- 
gen, and oxygen ; the oxygen be- 
ing exactly sufficient to convert 
all the hydrogen into water. 

Proportion of water to carbon, 
about 3 to 2. 

3 (a). Vegetable acids {and pectous 
substances.) 

Substances containing no nitro- 
gen, but made up of carbon, hydro- 
gen and oxygen ; the oxygen be- 
ing generally in greater amount 
than is sufficient to convert all the 
hydrogen into water. 



4. Salts {mineral). 



Examples. 


Functions. 


- 

Animal : 




Albumin, 


Formation and repair of tis- 


Fibrin, 


sues and fluids of the body. 


Syntonin, 


Regulation of the absorption 


Myosin, 


and utilization of oxygen. May 


Globulin, 


also form fat and yield energy 


Casein. 


under special conditions. In 


Vegetable : 


most foods the above, both ani- 


Glutin, 


mal and vegetable, are largely 


Legumin. 


converted into albumoses and 




peptones. 


Gelatin, 


These perform the above 


Ossein, 


functions less perfectly, or 


Chondrin, 


only under particular circum- 


Keratin, 


stances. 




These substances appear es- 
sential as regulators of diges- 






tion and assimilation, especi- 




ally with reference to the gela- 




tin group. 


Olein, 


Supply of fatty tissues ; nu- 


Stearin, 


trition of nervous system ; sup- 


Margarin, 


ply of energy and animal heat 




by oxidation. 


Starch, 


Production of energy and 


Dextrin, 


animal heat by oxidation ; 


Cane sugar, 


form fats and possibly some 


Grape •' 


proteid. 


Lactin (or 




milk sugar) 




(More than 


Preserve the alkalinity of the 


is sufficient 


blood by their conversion into 


to convert 


carbonates ; furnish a small 


all H into 


amount of energy or animal 


H 2 0.) 


heat by oxidation. 


Oxalic acid, 




Tartaric " 




Citric " 




Malic " 




(No excess 




ofO.) 




Acetic acid, 




Lactic " 




Sodium 


Various ; support of bony 


chloride, 


skeleton, supply of HC1 for 


Potassium 


digestion, etc. Regulators of 


chloride, 


energy and nutrition. 


Calcium 




phosphate, 




Magnesium 




phosphate, 




Iron. etc. 





202 A MANUAL OF HYGIENE AND SANITATION. 

Dietetics mean u a systemic regulation of the diet for 
hygienic or therapeutic purposes. " It considers all the 
factors that affect the proper digestion and assimilation 
of food. For instance, it is not alone necessary to deter- 
mine just what substances, in a chemical sense, the body 
needs to sustain life and maintain health. Nor is it suffi- 
cient to say that a man must have just so much of this 
and so much of that food, for there must always be a 
variation in both kind and quantity to meet the chang- 
ing demands of the system. With a few exceptions, no 
matter how toothsome or healthful a certain food may 
be, it soon palls upon the appetite if necessity compels 
its continued use for a prolonged period, and this dis- 
gust may be so impressed upon the memory of the senses 
as to cause them to prevent the use of that food forever 
after. 

The aesthetic factors in the preparation and serving of 
food must also be taken into account, and the question 
of pleasing the taste and appetite has much to do with the 
progress and completeness of digestion. Other things 
being equal, palatable and agreeable foods are disposed 
of much more satisfactorily than others not so, and physi- 
cians and others should learn that especially in sickness 
the appearance and palatability of a food have much to 
do with its acceptance, not only by the patient, but by 
his stomach as well. Cleanliness and neatness in food, 
china and napery are of greater value than expense or 
show, and a little attention and tact in such matters will 
often enable a patient to take, enjoy and retain food and 
nourishment, even when he or she asserts and believes 
this to be impossible. 

Another factor of much importance in the digestion of 
food, but one too often too lightly considered, is the mood 



FOOD. 203 

or state of mind when the food is taken and while it 
remains in the alimentary canal. There is more than 
moral philosophy in maintaining a cheerful and a tran- 
quil disposition during the daily meals and for a time 
thereafter; while there are numerous instances of most 
serious results occurring from the giving way to anger or 
other intense emotiou at such times, the digestive func- 
tions being either completely checked, or, what is fre- 
quently worse, so altered that their products are actually 
toxic in their character. And is not a dyspeptic often so 
because of his pessimism, rather than a misanthrope be- 
cause of his indigestion ? 

Before proceeding further it will be well to consider 
briefly the physiology of digestion in so far as it concerns 
the chemical changes occurring in the food while it is in 
the digestive tract. These changes are brought about by 
the action of certain bodies secreted or made by the diges- 
tive organs and glands, which we have been in the habit 
of calling unorganized ferments, but which would, per- 
haps, better be known hereafter as enzymes. Unorganized 
ferments are so called because they have not the definite 
cell-formation, life and power of reproduction which be- 
long to the yeasts, mould-fungi and bacteria which bring 
about the fermentative changes in organic substances so 
commonly within the knowledge of everyone, such as the 
conversion of saccharine solutions into alcohol, of alcohol 
into acetic acid, etc. 

But though unorganized, the enzymes likewise act upon 
organic matter; for example, upon the food which we eat, 
and — like the other ferments — they apparently do this 
simply by their presence rather than by entering into 
actual combination with the matter acted upon, as do 
ordinary chemical reagents. They are undoubtedly the 






204 A MANUAL OF HYGIENE AND SANITATION. 



products of glandular protoplasm, probably proteid in 
nature, and some, at least, very likely belonging to the 
group of nucleo-albumins, which latter form a component 
part of every organic cell. 

The knowledge of the digestive functions will be greatly 
simplified for the student if he remembers that " with the 
possible exception of the coagulating enzymes, the action 
of the enzymes is that of hydrating agents: they produce 
their effect by what is known as hydrolysis — that is, they 
cause the molecules of the substance upon which they act 
to take up one or more molecules of water; the resulting 
molecule then splits or is dissociated, with the formation 
of two or more simpler bodies." 1 

Thus the insoluble proteids and carbohydrates become 
respectively the soluble peptones and sugars of their allies, 
capable of being absorbed into the myriad capillaries that 
are distributed throughout the lining membrane of the 
alimentary tract; and even the change that takes place 
in fat when digested is one, that involves the taking up of 
some water. 

There are four characteristics of the enzymes worthy of 
note: 1. That they are all soluble in water and glycerin, 
the latter being specially useful in making stable prepara- 
tions of them from the organs producing them. 2. " That 
very low temperatures (0° C) retard or suspend entirely 
their action, without, however, destroying the enzyme; 
that for each enzyme there is a temperature at which its 
action is greater," and that " in a moist condition they 
are all destroyed by temperatures below the boiling-point; 
60° to 80° C. are the limits actually observed." 2 3. " That 
they never completely destroy the substance upon which 

i American Text-book of Physiology, first edition, p. 219. 8 Ibid. 






FOOD. 205 

they act/' probably being retarded by their products when 
the latter reach a certain percentage. " When these are 
removed the action of the enzymes begins again." 4. 
" Except for very small quantities, it may be said that 
the amount of change caused is independent of the amount 
of enzyme present;" or, rather, " with increasing amounts 
of enzymes the extent of action also increases, reaching a 
maximum with a certain percentage of enzyme; increase 
of enzyme beyond this has no effect." The amount of 
work capable of being done by a small proportion of an 
enzyme is enormous, good pepsin, for instance, having 
the power of converting 2500 times its own weigh! of 
proteid; but we must remember that this power is not 
infinite, and that after a time the enzymes will cease to 
act. 

There are five groups or classes of enzymes concerned 
with the proper digestion of food to be found in the 
animal body, and it is interesting to note that examples 
of^each of these classes are also to be found in various 
members of the vegetable world. The two principal 
remaining classes, being neither of animal origin nor 
digestive agents, need only be mentioned here : They are 
the glucoside-splitting and urea-splitting enzymes, the latter 
being produced by certain bacteria and converting urea 
into ammonium carbonate. 

Considering the digestive processes in their order as the 
food proceeds from the mouth through the alimentary 
canal, we find that the first active secretion or fluid is the 
saliva, and that its enzyme is ptyalin, belonging to that 
group which converts the insoluble carbohydrates (starches) 
into soluble sugars, maltose, etc. Ptyalin acts best in 
neutral or slightly alkaline media, at about the body tem- 
perature (40° C.),and upon cooked much better than upon 



206 A MANUAL OF HYGIENE AND SANITATION. 

raw starch. 1 Its action is retarded or totally checked by 
a low temperature or by strongly alkaline or moderately 
acid solutions, and the enzyme itself is probably destroyed 
by an increase in acidity equal to that of the gastric juice, 
or by a temperature of 65° or 70° C. The reason it con- 
verts cooked starch so much more quickly is probably 
because the heating process breaks up the cellulose en- 
velopes upon which the ptyalin has almost no effect and 
which protect the starch granules within from its action. 
The heat also causes a very close union between the 
molecules of starch and water, this facilitating the later 
hydrolysis by the enzyme. 

In addition to its digestive function, the saliva also 
serves to moisten dry food so that it may be swallowed, 
and to dissolve sapid and savory substances that they may 
be duly appreciated by the organs of taste. 

Our first hygienic lesson in regard to the digestive 
functions is, therefore, that in order to get the full benefit 
of the salivary secretions, all food, and especially that of 
a starchy nature, should be well masticated and retained 
in the mouth for some little time, instead of its being 
" bolted 7 ' at once or after a hasty bite or two. Nor 
should very cold or very hot beverages be taken at the 
same time with the food, for not only will the action of 
the ptyalin be thus retarded or destroyed, but that also, 
as we shall see, of the gastric juice within the stomach. 
A note here as to the drinking of water at meal-time will 
not be out of place. A moderate quantity of proper tem- 

1 Kubel claims to have found that an alkaline reaction, even when very weak, 
actually interferes with ptyalin digestion, but that it is favored by a weak acid 
reaction, especially if the acid be one of the stronger ones, like HC1. He admits 
that an amount of hydrochloric acid equivalent to that of the gastric juice checks 
the activity of the ptyalin, but believes that at the beginning of a meal and for 
a time thereafter salivary digestion takes place better in the stomach than in the 
mouth. (Boston Medical and Surgical Journal, April, 1899.) 



FOOD. 207 

perature will probably be beneficial than otherwise, since 
it helps in the solution of the food; but an excessive 
quantity tends to do harm by diluting the enzymes too 
much, thus interfering with their reactions, and by inter- 
fering with the absorption of the digested matters. 

The food, having passed from the mouth to the stomach, 
may still be acted upon for a time by the ptyalin until the 
work of the latter is checked by the acid of the gastric 
juice. 1 The energy of digestive action is then transferred 
from the starches to the proteid constituents of the food, 
the chief enzyme now being pepsin, though we also find 
in the gastric juice a coagulating ferment — rennin — which 
acts upon soluble proteids, like the casein of milk, to form 
clots or curds. 

Pepsin acts only in an acid medium (the acidity being 
supplied normally by the free hydrochloric acid of the 
gastric juice), and best at the body-temperature. As 
stated, extremes of temperature are adverse to its activity 
and may check it altogether, and, likewise, too much or 
too little acid may have the same effect, from 0.2 to 0.3 
per cent, of HC1 being the normal amount and giving the 
best results. Rennin seems in the normal stomach to act 
only on the casein of milk, and curdles this probably be- 
cause it is then more easily digested by the pepsin and, 
later, by the trypsin of the pancreatic juice. 

The action of the pepsin plus the acid upon the proteids 
of the food is a hydrolytic one, and the end-products are 
practically hydrated proteids, called albumoses and pep- 
tones — substances especially diffusible and capable of 
absorption. The gastric digestion, therefore, after the 

1 Recent experiments seem to show that " ptyalin digestion normally continues 
during the first hour of gastric digestion, or, in fact, until the hydrochloric acid 
secretion reaches the normal maximum." (A. L. Benedict, M.D. : Journal of the 
American Medical Association, July 28, 1900.) 



208 A MANUAL OF HYGIENE AND SANITATION. 

action of the ptyalin has been checked by the acid gastric 
juice, practically has to do only with the albuminous or 
nitrogenous part of the food, the remainder, or at least 
that part of it not yet capable of absorption, remaining 
unchanged until it passes further on into the intestines. 
Soluble salts, sugars and part, at least, of the peptones as 
they are formed, may, however, be taken up by the stom- 
ach capillaries, while the rest of the food-mass, kept ever in 
motion by the muscular movements of the stomach -walls, 
is being thoroughly mixed and converted by the peptic 
action into the semi-liquid substance called chyme, which 
is passed at intervals and in small quantities through the 
pyloric opening into the duodenum. Long before the 
stomach has entirely emptied itself — which may only be 
after several hours of activity — intestinal digestion is 
well under way, and in some respects this is the most 
important as well as the most comprehensive process of 
all. The three secretions to whose combined action the 
chyme is now subject are the pancreatic juice, the bilo, 
and the intestinal juice. All are alkaline and quickly 
neutralize the gastric acid; it scarcely need be noted, 
then, that the remaining enzymes act best or only in 
alkaline media, though one of them, trypsin, may act in 
solutions not too strongly acid. 

In the pancreatic juice we find three enzymes, practically 
the only remaining ones of much importance; although in 
the rather scanty intestinal juice two others have been 
found, one capable of converting starch into sugar, and 
the other inverting cane-sugar into levulose and dextrose. 
The bile contains no enzymes. The pancreatic ferments 
are trypsin, which acts upon proteids and albuminoids 
even more powerfully than pepsin, and likewise converts 
them into peptones; amylopsin f which is practically identical 



FOOD. 209 

with ptyalin in its function ; and steapsin, which causes 
neutral fats to take up water and split into free fatty 
acids and glycerin. 

Under the action of the trypsin all that portion of the 
proteid food which has not been completely digested in 
the stomach reaches that stage in the small intestines and 
is absorbed therefrom. In fact, it is very probable that 
the tryptic digestion is often the more important of the 
two. As the action of the saliva upon the carbohydrates, 
which form the greater bulk of our food, must of neces- 
sity be very limited, it is evident that almost all of the 
starch digestion is performed by the amylopsin, aided 
in slight measure by the similar enzyme of the intestinal 
juice. The salts and other soluble elements of the food 
have already been absorbed, and there remain only the 
fats or hydrocarbons. 

Under the influence of the steapsin a comparatively 
small portion of the fat in the food is separated into 
glycerin and free fatty acids, and this action for some reason 
takes place much more rapidly when aided by the bile than 
with the pancreatic juice alone. Then these fatty acids 
unite with the alkalies and alkaline salts Of the above 
secretions, but especially of the bile and intestinal juice, 
to form soaps, and these soaps aid in emulsifying the 
remainder of the fats and in thus making them ready for 
absorption, which latter process is also facilitated by the 
direct action of the bile upon the intestinal epithelium. 

The student must not get the idea that the absorption 
of digested food from the alimentary canal is merely a 
physical process and a matter of osmosis or diffusion. 
Accumulating experience indicates that it is in a measure, 
if not largely, vital and physiological, and that " the 
living cells of the intestinal wall appear to take an active 

14 



210 A MANUAL OF HYGIENE AND SANITATION. 



share in the process, and modify the action of the physical 
factors in a manner not at present understood." This is 
probably especially true as regards the absorption of the 
fats, whether we take the commonly accepted view that 
most of the fat is emulsified and only a small portion split 
up and saponified in the intestine, or the one which some 
have advocated of late years, viz., that almost, if not all, 
of the fat is decomposed and dissociated, and compara- 
tively little, if any, emulsified. 

The digestive processes having been thus outlined, it 
will be well to learn how they may be maintained as 
complete and perfect as possible. In the first place, the 
cooking of food is usually an essential preliminary. We 
cook meats not only to make them more agreeable to the 
palate, but also to facilitate digestion. The effect of 
cooking upon muscle (flesh) is "to loosen the bundles of 
fibrillae from each other, so that they are readily torn 
asunder or crashed by the teeth," while the various con- 
nective tissues are softened and gelatinized, not only thus 
becoming more digestible and nutritious, but allowing the 
histologic elements which they bind together to separate 
and be more freely acted upon by the solvent fluids. So 
with the vegetables, the heat and steam soften and rup- 
ture the cellulose envelopes of the various cells that the 
ferments may the more readily act upon their contents; 
and at the same time they bring about subtle chemical 
changes that greatly increase the palatability of the food- 
stuffs. 

Thorough mastication of the food is important for the 
reasons already stated, and the cause of most dyspepsias 
may be found in faulty habits of eating. Foster says 
that in the stomach " the natural bundles of meat and 
vegetables fall asunder, the muscular fibres split up into 



FOOD. 211 

disks, and the protoplasm is dissolved from the vegetable 
cells;" but, " if the meat be not chewed properly, but 
' bolted/ the solveut gastric juice can only act on the 
exterior of the mass, while 'lumps' offend the stomach 
and arrest the gastric secretion." The importance of 
abstaining at meal-time from beverages or other sub- 
stances of too low or too high a temperature has already 
been noted, and, as all the enzymes act best at the body- 
temperature, care should always be had to avoid the 
chilling of the abdominal organs while digestion is under 
way. 

Again, as the formation and action of the enzymes 
begin with the ingestion of food and depend largely upon 
a sufficient blood-supply to the organs concerned as long 
as digestion continues, it is essential that the blood-current 
shall not be diverted from these organs during this period 
by excessive mental or physical demands, and that a con- 
dition of cheerfulness, repose and rest should wisely follow 
every meal. Regularity as to the time of meals and the 
avoidance of too great a tax upon any of the organs by 
over-indulgence or intemperance in eating are likewise 
both important matters and ones too often neglected. 

It is interesting to note that in certain members of the 
vegetable kingdom are to be found enzymes very similar 
to the normal ones of animal origin just considered, and 
that where the latter appear to be deficient in quantity or 
action, these kindred ones may be sometimes used with 
advantage. Thus, in the pineapple and in the papaw are 
ferments akin to pepsin or trypsin, and in the former an- 
other with the same action as rennin. All are familiar 
with the diastase of germinating seeds and its use in the 
making of beer, but not so common is the knowledge that 
other seeds contain fat-splitting enzymes much like steap- 






212 A MANUAL OF HYGIENE AND SANITATION. 



sin. But though these extraneous digestants may be val- 
uable and advantageous as therapeutic agents when an 
actual cessation of normal function makes them necessary, 
a caution should be interpolated here regarding the custom 
or habit that may be acquired of depending too much upon 
them, especially by persons, otherwise healthy, whose 
digestive functions are somewhat deficient. A better 
plan is to bring those functions up to the normal in 
strength and vigor by the observance of hygienic rules 
and a well-considered method of life. 

The Amount of Food Necessary to Life and Health. 
Considerable work has been done to determine just what 
amount of the proximate food principles the average per 
son requires daily, and in this respect Moleschott's tables 
are quite generally accepted, having been constructed from 
data gained by actual experiment and also by the con- 
tinued observation of the effects of a number of dietaries. 
According to these tables, a man weighing 160 pounds 
and doing work equivalent to 300 foot-tons per diem will 
need about 4.6 ounces of proteids, 3 ounces of fats, 14.25 
ounces of carbohydrates, and a little more than 1 ounce 
of salts. Prof. Vaughan believes that the average work- 
ing man in America requires daily, in round numbers, not 
less than four ounces of proteids, two ounces of fats, and 
eighteen ounces of carbohydrates. 

It is essential that the proper proportion between the 
ingested nitrogen and carbon should be maintained, and 
this should be as one of the former to fifteen of the latter. 

In addition, the individual needs from 70 to 100 fluid- 
ounces of water daily, a good part of which, however, is 
normally taken with the food. It must be remembered 
that the above figures only represent average amounts, 
and that climate, amount of exercise, the size and activity 



FOOD. 213 

of functional and excretory organs, and personal peculi- 
arities all serve to modify them in the case of any special 
individual. 

Other conditions not interfering too greatly, any com- 
bination of foods giving the above amounts of the proxi- 
mate principles at a reasonable cost will be an economical 
and healthy diet, provided such food is acceptable to the 
palate, is digestible, and contains nothing harmful to the 
system. 1 

Fothergill thinks that, as a rule, we take too much pro- 
teid food, especially in the form of meat, and that, though 
this goes in the main for tissue repair, the latter requires 
much less of such food than we ordinarily suppose, and 
that the system does not need so very much of albumin 
or its equivalents. In this he may be correct to a certain 
degree, particulary as regards his fellow-Englishmen, who 
are notorious meat eaters, and as to the facts that tissue 
waste is comparatively slight and that the body frame- 
work rusts out rather than burns out. But in addition 
to the statements already made — that part of our nitrog- 
enous food regulates the demand for oxygen, that part is 
doubtless a source of energy and that still another part 
mav be converted into fat — we should also remember that 
animal food is a concentrated food, that much energy has 
been expended in converting and storing it up from the 
vegetable world, that it is stimulating, and that our di- 
gestive organs resemble more closely, at lea^t as far as 
comparative weight is concerned, those of the carnivora 
rather than of the herbivora. These reasons, as well as 
the fact that proteids make up a considerable part of the 

1 For such combinations, see Vaughan's Healthy Homes and Foods for the 
Working Classes, and Mrs. Abel's Practical, Sanitary, and Economic Cooking. 
Both are essays published by the American Public Health Association. 






214 A MANUAL OF HYGIENE AND SANITATION. 

■ 

only typically complete food that we have and which 
nature gives to the mammalian infant, indicate that 
we should be as careful not to use too little as too much 
nitrogenous food. 

The proteid portion of our food is obtained from the 
albumin of meat and fish, from milk and eggs, and from 
the gluten of cereals and the vegetable casein (albumin) 
of the leguminous plants, such as peas, beans, etc. The 
proportion and properties of the albuminous matter vary, 
of course, in each of these, and even in the same substances 
under different circumstances; but all should be taken into 
consideration and used interchangeably if we wish to obtain 
the greatest variety and benefit in feeding, together with 
due economy of expense. 

In this connection attention may be again directed to 
the peculiar fact that the leguminous plants, through the 
aid of certain species of bacteria, are able to absorb and 
store up in the form of proteids a considerable quantity 
of nitrogen from the surrounding atmosphere, and that 
these plants are, therefore, an important source of food- 
supply. 

The carbohydrates that furnish food to the body and 
are one of the sources of the heat and energy upon which 
muscular motion and vital activity depend, are practically 
all derived, with the exception of milk sugar, from the 
starches, sugars and gums of the vegetable kingdom. 

It has already been shown that much the greater part 
of the digestion of carbohydrate food is due to the action 
of the pancreatic enzyme — amylopsin — but we should not 
forget the action of the saliva, nor that thorough mastica- 
tion greatly assists the subsequent digestion by breaking 
up the starch granules and exposing them more freely to 
the action of the digestive juices. The latter object is 



FOOD. 215 

also obtained by crushing the cereals and by cooking the 
starch-bearing foods, for "grinding and cooking lessen 
the labor of the jaws and salivary (and pancreatic) 
glands/' 

After the end-products (dextrose, levulose, etc.) of car- 
bohydrate digestion have been absorbed from the alimen- 
tary canal, part of them, at least, are reconverted iu the 
liver into animal starch or glycogen, and this portion be- 
comes a part of the body-store of fuel. Fothergill says : 
"The liver stores up from each meal so much glycogen 
and gives it off as required; otherwise life would only be 
one dreary meal/' Another and perhaps greater moiety 
of the digested carbohydrates is converted into fat and 
stored away as adipose tissue in various parts of the body, 
as a fuither reserve of fuel for any emergency. " Many 
authorities state that fat is formed directly from carbohy- 
drates, and the weight of evidence appears to favor this 
view; but whether it is so formed directly, or indirectly 
by retarding the metabolism of the fatty and proteid con- 
stituents of the food, there is no doubt that the consump- 
tion of carbohydrates results in theformatiou of fat within 
the body. 771 Moreover, " whatever the mixture of fats 
taken in as food, the fat of the body always has the same 
composition; this fact agrees with the conclusion that the 
metabolism and deposition of fat in the body are due to 
cell activity, and that the fat comes in part from the pro- 
teid and part from the carbohydrate foods. 772 

Another important function of the carbohydrate foods 
is the formation by their metabolism in the body of lactic 
and other acids, which are of the greatest value in 
nutrition and in maintaining the normal reactions of the 

1 Notter and Firth : Treatise on Hygiene, p. 254. '- Ibid., p. 253. 



216 A MANUAL OF HYGIENE AND SANITATION. 

body-fluids. This is perhaps one of the chief reasons why 
fats and carbohydrates are not interconvertible in any 
prolonged dietary. 

Fat is essentially a compound of glycerin with one or 
more fatty acids, usually stearic, palmitic and oleic. 
The digestibility of a fat largely depends upon its being 
fluid at the body-temperature ; therefore, as the melting- 
point of stearine is higher than this, the more of it that a 
fat contains, the less digestible and nutritious will the 
latter be. For this reason butter is more digestible than 
suet, lard than mutton-fat, etc., and the more assimilable 
cod-liver oil is that from which the stearine has been 
removed. 

Fat for food is derived from vegetable as well as 
animal sources, many seeds and nuts and some cereals, 
as oats and corn (maize), containing much fat. By im- 
proved methods it is becoming possible to supply fats in 
purer, cheaper and more agreeable forms, so that they 
can now be freely used even by the poor, the very class 
that needs them most. 

Under normal conditions it is probable that the body- 
fat or adipose tissue is almost never derived from the fat 
in food, but rather, as stated, from the proteids and car- 
bohydrates. But fat is also an essential part of tissue- 
structure, making up more than one- fifth of the solid 
matter of the brain and nerve tissues and one-sixth of 
muscle, and possibly serving as fuel when the cell con- 
tents are oxidized; and it is not impossible that this fat 
of active tis_sues may come in part from that ingested as 
food. The writer has already hinted at the possibility of 
a combination of the newly absorbed fat with the argon 
of the atmosphere in the lungs and the consequent forma- 
tion of new cells or vital material. In any case, however, 



FOOD. 217 

fat is a very necessary part of a man's diet, for not only 
is a small quantity necessary to the digestion of proteids, 
causing the formation in the body of larger amounts of 
fat than the quantity ingested and greatly improving the 
physical condition; but it may be and, when occasion 
requires, undoubtedly often is used directly as fuel with- 
out first being stored up in the tissues. , 

As it is a concentrated fuel-food, it is to be used freely 
when we want to keep the body warm or when we need 
extra force for any increased exertion. " On a diet rich 
in fat great muscular effort can be undergone with but 
little destruction of muscular tissue, and without increased 
urea discharge/' The object of fat in the diet, then, 
may be said to be to give heat and energy as fuel, and, 
when necessary, to aid in the repair or building up of 
active tissue. 

The constructive property of fat is especially valuable 
in the treatment of all wasting diseases, especially phthisis. 
Fothergill emphatically declares that u the great food for 
the strumous is fat/' and also says : " Whenever there 
is any tendency to tubercle the individual should learn 
to eat fat, just as a seafaring man learns to swim. As a 
physician to a chest hospital, I have learned to dread the 
announcement that fat is no longer taken, especially if the 
individual is of strumous build, with a small, narrow 
chest. In my opinion, the existence of a considerable 
area of affected lung where the digestive powers keep up 
is less fraught with evil and less prognostically significant 
than intractable wasting with very little disease in the 
lung." In this connection, note that an excess of pro- 
teids in the diet causes a more rapid oxidation of fat, and 
that an excess of fat or of carbohydrates lessens the ab- 
sorption of oxygen and the oxidation of both fats and 



218 A MANUAL OF HYGIENE AND SANITATION. 

proteids. Also, that the free use of fluids is thought to 
favor an increase in the quantity of fat deposited in the 
body. 

Fat is practically indigestible in the stomach, and some 
stomachs cannot tolerate it, especially when taken with 
other food ; although usually a little fat assists in the 
digestion of proteids by stimulating the secretion of the 
gastric juice. Cases occur not rarely in which it is neces- 
sary that comparatively large quantities of fat should be 
ingested and yet in which there is apparently decided gas- 
tric intolerance of it. In such event success is often to 
be attained by giving the fat some little time after the 
regular meals, when the gastric digestion is approaching 
completion and the chyme is being passed out of the 
stomach to be further subjected to the action of the intes- 
tinal digestants. It may also be well to emulsify it 
partially or wholly, especially if there be faulty secretion 
of bile and pancreatic juice, and sometimes to disguise its 
taste with agreeable aromatics or flavors. In this way 
there is generally but little trouble in administering fats, 
even such as those which, like cod-liver oil, have a dis- 
agreeable taste and odor. Failing in this, we may still 
resort to inunctions, preferably of predigested or emulsi- 
fied fats, and often with considerable advantage, since it 
has been experimentally shown that after passing through 
the skin, fat may be taken up by the subcutaneous lymph- 
atics and later be oxidized or metabolized almost as com- 
pletely as if it had entered the system by way of the 
intestinal canal and thoracic duct. 

Certain salts in certain proportions are necessary for 
the maintenance of health in the body. " Lime, chiefly 
in the form of phosphate, is absent from no tissue, and 
there is reason to think that no cell-growth can go on 



FOOD. 219 

without it." Even the bacteria must have earthy phos- 
phates for the purposes of growth. Chlorine, derived 
largely from the sodium chloride of food, is necessary to 
form the hydrochloric acid of the gastric juice, the chlo- 
rides also keeping in solution the globulins of the blood 
and body fluids and helping to dissolve the albumin. 
Phosphorus is necessary in the formation of the lecithin 
of nerve tissues, as well as for the phosphates above men- 
tioned, and those of potassium, magnesium, etc., which 
go to form bone. Potash salts maintain the alkalinity of 
the solid tissues, and soda salts that of the body fluids. 
Iron is essential for the construction and nutrition of the 
blood-corpuscles, though small quantities of it are to be 
found in almost every other tissue. 

But not only must the above inorganic salts be given 
in proper supply, but also certain ones of organic nature, 
in order to prevent conditions of malnutrition or disease. 
Those especially which are changed to form carbonates, 
as the lactates, tartrates, etc., or their respective acids, 
help to maintain the alkalinity of the system and appear 
to be most essential, as a scorbutic condition seems to be 
inevitably created or fostered by their absence. There is 
also some evidence that certain gouty conditions may be 
due to the removal of the natural vegetable salts by un- 
wise methods of cooking. The fact of the carbohydrates 
being an important source of these organic acids and salts 
has already been mentioned. 

Lastly, with many of our foods we require the addition 
of certain flavors, condiments, etc., which, though they 
have little or no real food value in themselves in the 
sense of repairing tissue or furnishing energy, do much 
good, when not abused, by making the food more pala- 
table, by stimulating the secretion of the digestive fluids, 



220 A MANUAL OF HYGIENE AND SANITATION. 

and by acting as carminatives. These condiments should 
not be omitted from the food of the sick or convalescent, 
for they have a value of their own, and are " agreeable 
to the palate and, in moderation, good for the digestive 
organs." 

As a review of the preceding statements, the following 
quotation, from Notter and Firth, 1 may be of value : 

" With regard to the necessity for all four classes of 
aliments, it can be affirmed with certainty that (putting 
scurvy out of the question) men can live for some time 
and can be healthy with a diet of proteids, fats, salts and 
water. But special conditions of life, such as great exer- 
cise or exposure to very low temperature, appear to be 
necessary, and under usual conditions of life, health is not 
very perfectly maintained on such a diet. It has not yet 
been shown that men can live in good health on proteids, 
carbohydrates, salts, and water, etc., without fat. 

" The exact effect produced by the deprivation of any 
one of these classes is not yet known. An excess of the 
proteids causes a more rapid oxidation of fat, while an 
excess of fat lessens the absorption of oxygen and hinders 
the metamorphosis of both fat and albuminous tissues. 
The carbohydrates have the same effect when in excess, 
and appear to lessen the oxidation of the two other classes. 

^^ It is generally admitted that the success of Banting's 
treatment of obesity is owing to two actions : the increased 
oxidizing effect on fat consequent on the increase of meat 
(especially if exercise be combined), and the lessened in- 
terference with the oxidation of fat consequent on the 
deprivation of starches. 

u Health cannot be maintained on proteids, salts, and 

1 Treatise on Hygiene, p. 256. 



FOOD. 221 

water alone ; but, on the other hand, it cannot be main- 
tained without them/' 

It will be impossible to go into details concerning all 
the articles commonly used as foods, but there are certain 
facts that should be well known and which cannot properly 
be omitted from a work of this kind. 

Milk is a typical food-stuff, complete in itself, in that it 
contains all the food principles, and these in nearly the 
proper proportion, at least for infant life. The casein 
and albumin represent the proteids ; the cream, the fats 
and the lactose or milk-sugar is a concentrated carbohy- 
drate —all being in combination with sufficient salts and 
water. 

It should constitute almost the sole food of infants dur- 
ing the earlier months of life ; and that it is capable of 
sustaining adult life almost indefinitely, especially where 
there is little demand for heat or the expenditure of force, 
has been shown in numerous instances. 1 Coplin and 
Bevan mention the case of a patient who lived and thrived 
on milk alone for over thirteen months, and of another 
who lived for three years on the same diet. But, of 
course, the limited proportion of carbohydrates, even 
though concentrated, is not all-sufficient for the mainte- 
nance of great vital activity, and for persons in ordinary 
life some addition to the diet is necessary. 

The albumin of milk is coagulated by heat, but the 
casein, which constitutes the greater part of the proteid 
element, is clotted by an acid or by an enzyme, such as 
rennin ; and as both of these are present in normal gastric 
juice, it would seem that the preliminary coagulation of 

1 It is understood, of course, that in order to be a proper food for young infants, 
cow's milk must be modified so as to resemble human milk as nearly as possible, 
and so as to give the proportion of the respective food principles which each par- 
ticular case may need. 



222 A MANUAL OF HYGIENE AND SANITATION. 

casein was essential to its proper digestion. It should be 
remembered, however, that the casein of cow's milk forms 
a much harder and firmer clot than does that of human 
milk, and that the former should, therefore, never be 
hastily introduced into the stomach in large volumes, but 
should rather be taken slowly and preferably with other 
food which will help to divide the curd mechanically. 
In the feeding of children, an alkali, such as lime-water, 
is thought to soften the curd when mixed with the milk, 
and to possibly facilitate digestion. 

Outside of the body, fermentative changes due to certain 
bacteria may convert the milk-sugar into lactic acid, 
which coagulates the casein and " sours" the milk. 
Another peculiarity of casein is the tenacity with which it 
holds large quantities of phosphate of lime, one of the 
most valuable of food-salts. 

Sometimes it is advantageous or necessary to predigest 
milk for infants or sick persons, but if the digestion be 
carried beyond a certain point, the consequent peptones 
and albumoses will give the milk a bitter and disagreeable 
taste. In the feeding of infants it must not be forgotten 
that the percentage composition of human milk is different 
from that of cow's milk, and that the latter will need 
dilution to decrease the proteid proportion, but an increase 
of fat and carbohydrates. As a child grows older and 
more active, it becomes necessary to add to the milk addi- 
tional carbohydrates, which should be easy of digestion 
and soluble, milk-sugar and predigested starches in the 
form of maltose and its allies being preferable. 

Milk should always be kept as cool as possible and in 
closed vessels, not only to prevent the absorption of dis- 
agreeable odors and harmful gases, to which it is very 
prone, but to exclude dirt and bacteria. As it is an 



FOOD. 223 

excellent culture medium, and as it is commonly liable 
to be exposed to contamination by organisms from many 
sources before it reaches the consumer, fermentative or 
other harmful chemical changes are almost certain to 
occur in it if the temperature conditions are at all favor- 
able. For this reason, it is necessary that the greatest 
care should be used in the handling of the milk from the 
time it leaves the cow until it is used, and for the feeding 
of children and whenever there is any possibility of it 
being the carrier of disease germs of any kind, it should 
be properly sterilized and then kept sterile until used. 
In fact, sterilized milk, modified to resemble the human 
secretion, will usually be superior to any other artificial 
food for infants, but the sterilization should always be 
done before fermentation has begun and harmful products 
have been developed in the milk. The sterilization may 
slightly alter the taste and other properties of the milk by 
coagulating the albumin, but it is doubtful whether it 
makes any real change in its digestibility. 

The cream of. milk is fat in its most digestible and ac- 
ceptable form, and should not be removed from milk if 
the latter is to be used as food. If the milk seems to be 
too rich, it may be advisable to skim it, giving it in some 
form or other with the regular meal, and reserving the 
cream until a couple of hours or so later, when gastric 
digestion is approaching completion. One may also often 
avoid the use of cod-liver oil and similar fats by taking 
cream — either plain or whipped and flavored — in this way 
some little time after the meals. 

Skimmed milk and buttermilk may be used freely as 
beverages, as both are refreshing and healthful with 
some little food value ; buttermilk is also acceptable to 
many persons on account of its lactic acid. (( Koumiss" 



224 A MANUAL OF HYGIENE AND SANITATION. 

and "kefir" are both prepared from milk through the 
action of certain fermentative organisms, which also 
bring about a partial digestion of the casein. Each con- 
taius carbonic and lactic acids, though in different propor- 
tions, some peptones or albumoses, and a very little alcohol. 
They are wholesome, agreeable to most palates, and are 
usually retained and utilized by stomachs rebellious to 
almost all other foods. 

Milk may be a factor in the causation of disease in a 
number of ways. Large and tough curds of cow's milk 
in the stomach often cause mechanical irritation and indi- 
gestion, especially in young children, and the products of 
the fermentative action already referred to are a frequent 
source of serious intestinal disorders ; while if further de- 
composition occurs, a very poisonous ptomaine, called tyro- 
toxicon, is apt to be developed and to cause even fatal 
results to those using the milk. This same substance is 
also liable to occur in any milk-product, such as cheese 
or ice-cream, and is usually the cause or agent in the cases 
of poisoning by such products that are so frequently 
reported. 

Again, the active principles of plants which the cow 
has eaten may be transmitted by the milk and produce 
their physiological effects. But a graver question is 
whether disease may be transmitted directly from the 
animals to man by this almost universal food-stuff. Every 
one knows that the milk from sick cows may cause 
marked disturbance of health, and there now seems to be 
fair evidence that cattle are subject to certain diseases 
identical with or very similar to human maladies, the 
milk serving as a carrier for the contagium. 

Scarlet fever and diphtheria may be mentioned as dis- 
eases suspected of being transmitted in this way, and 



FOOD. 225 

there seems to be no longer any doubt in regard to tuber- 
culosis. Though some authorities still question whether 
this latter disease can be thus transmitted unless the milk- 
glands themselves are affected, the great prevalence of the 
disease among cattle and experimental evidence both make 
it certain that milk is often the means of transmitting the 
infection, and many believe that by far the larger number 
of the many cases of infantile tuberculosis have origin 
from this source. 

The condemnation and destruction of all cattle that 
show any symptoms of tubercular infection is certainly 
one of the most important and effective methods of check- 
ing the spread of and eliminating this very prevalent and 
deadly malady. The use of inoculations of tuberculin 
as a means of diagnosis has materially contributed to 
this eud, for by its aid the presence of the disease is often 
indicated in many animals that have as yet evinced no 
physical signs of the disease. 

Milk may also become a disease carrier through care- 
lessness in handling by infected persons or by the admix- 
ture with it of water containing disease germs. Epidemics 
of diphtheria, scarlet fever, typhoid fever, and cholera 
have all been traced to a contaminated milk-supply, and 
it is a question whether many of the more or less local 
outbreaks in cities are not of this character. The writer 
is personally cognizant of five cases of undoubted scarlet 
fever that occurred almost simultaneously in one locality 
and in which, apparently, the only common source was 
the milk-supply. He was unable to discover that there 
had been any illness either among the cattle or in the 
family of the milkman in question, but he has always felt 
that there was considerable evasion in replying to the 
inquiries made. 

15 



226 A. MANUAL OF HYGIENE AND SANITATION. 

The possibility of milk as a source of danger to health 
having been shown, the lessons to be had are these : that 
not only must there be the greatest care in the handling 
and keeping of milk until it is consumed, but there must 
also be frequent and careful inspection of the animals 
from which it comes and of their environment ; that no 
milk from any diseased cow should ever be used as food ; 
that wherever there is the suspicion or possibility of the 
milk being contaminated with disease germs, it must be 
thoroughly sterilized, and that any change from its normal 
condition should also forbid its use. 

Fortunately, good milk can almost always be had so 
cheaply and readily that no serious hardship inures in the 
strict observance of these rules, and the public should be 
educated to demand as well as to pay fairly for pure milk 
from healthy animals, these matters being even more im- 
portant than that the quality, as shown by analysis, 
should always be up to a certain standard. 

Good milk in bulk should be opaque, of clean ivory- 
white color, should have no peculiar smell or taste nor 
any deposit on standing. Nor should it show any change 
in taste or appearance upon boiling, excepting the forma- 
tion of the slight skin of coagulated albumin due to the 
heating. Details regarding the composition of milk and 
the methods for its examination will be found in the final 
chapter of this volume. 

The addition of preservatives to milk is very common, 
and should be discountenanced, not only because they are 
usually added in quantities harmful or prejudicial to health, 
but also, and almost more important, because milk should 
be supplied to consumers in such a condition and stage 
as not to need the preservative, and the presence of the 
latter is, therefore, suspicious. The same reasons also 



FOOD. 227 

justify the condemnation of the use of artificial coloring 
matters. The chemicals commonly used as preservatives 
are boric acid, salicylic acid, and formaldehyde. Of 
these, the salicylic acid is probably most harmful, as the 
habitual ingestion of even a moderate quantity is apt to 
be deleterious to the kidneys. (See page 240.) 

Cheese is a most valuable food-stuff, and, as a milk 
product, may be considered at this time. Good cheese 
usually contains twice as much nitrogen and three times as 
much fat as the same weight of meat, but many persons 
apparently find it difficult of digestion and can eat but 
little of it. This is perhaps because the nutriment is so 
concentrated and because, as usually eaten, it forms in 
the stomach a tough or pasty solid lump into which the 
gastric secretion cannot penetrate. Mattieu Williams has 
remarked that we habitually use cheese in the conditions 
in which it is most indigestible — either in its raw state or' 
cooked into a leathery mass — and he asserts that if the 
cooking is such that it is thoroughly mixed with other 
articles of food, or if we will masticate it with other food, 
so that this commingling of particles takes place, it will 
be found to be quite digestible by almost every one. He 
also advises the addition of a small amount of potassium 
carbonate in the cooking, as this favors the solution of 
the casein and replaces that salt which is removed in the 
whey. It goes without saying that, as a food, only 
cheese made from whole milk, or from that to which 
extra cream has been added, satisfies all requirements, and 
that skim-milk cheeses are decidedly less nutritious than 
those having the full proportion of fat. 

Butter, consisting as it does largely of the fat of milk, 
is a highly nutritions article of food and one of the most 
digestible of its class. It should be pure, sweet and 



228 ^ MANUAL OF HYGIENE AND SANITATION. 

free from rancidity, and while some of the substitutes 
offered in its stead are entirely wholesome, they should 
never be sold as butter or used to adulterate it. Neither 
should butter contain an excess of water nor of casein, 
as its food value, weight for weight, is thereby accord- 
ingly lessened. 

Eggs yield almost their full weight of food in a con- 
centrated and very digestible condition, and are valuable 
on this account, as well as for their palatability and their 
value in the preparation of many dishes. Although con- 
taining practically no carbohydrates, they have sufficient 
food material in themselves for the complete development 
of the living chick, with the aid of nothing external except 
the oxygen which passes through the shell : the lack of 
the carbohydrate element, ordinarily one of the essential 
food principles, is supplied by the heat from the mother 
hen or incubator, which is sufficient for the develop- 
ment and maintenance of the vital processes, since the 
unhatched creature wastes , almost no energy in physical 
activity. 

The white of egg is almost pure albumin with a little 
water and some salts ; the yolk contains about 30 per 
cent, of fat and some albumin. The albumin coagulates 
at about 170° F., but if it is exposed to a still higher 
temperature for any but a very short period of time, it 
becomes hard and difficult of digestion A so-called 
" soft-boiled" egg is scarcely more difficult of digestion 
than an uncooked one, and is certainly more palatable to 
almost every one. 

Eggs, milk and cheese may be made into many nutri- 
tious and palatable combinations which furnish food 
especially agreeable to the sick, as well as to those whose 
appetite and digestive functions have not been impaired. 



FOOD. 229 

Good meat, when deprived of its contained water, is a 
concentrated food, and is used not only on account of the 
large amount of nutriment it contains, but for its rich 
and agreeable flavor. It represents much vegetable 
matter converted into its present palatable and more 
digestible form by the metabolic activity of the animals 
from which it came. It contains all the essential food 
principles, the carbohydrates, however, being present as 
muscle sugar or inosite and, as in milk, in very small 
proportion. In all fresh meat there is much water, but 
more in lean meat than in fat ; fat bacon contains 60 per 
cent. ; lean beef, from 75 to 78 percent, of water. As the 
proportion of fat increases the quantity of albuminoids or 
proteids decreases: thus, lean beef may have only 2 per cent, 
of fat to from 20 to 24 per cent, of proteids, while bacon 
has about 24 per cent, of fat to 15 per cent, of proteids. 

Of the varieties of meat commonly used, beef is the 
most nutritious. Good beef should not be too pale nor 
too dark, should show no blood clots, have almost no odor, 
be elastic and not soggy to the touch, be well marbled 
with clean, white fat, and have compact flesh. Dark 
beef indicates that the animal was not properly bled, or 
has had some febrile disease ; wet and flabby meat, that 
it is approaching decomposition. The flesh of young 
animals is more tender than that of older ones, but not 
so digestible, partly because the young flesh cannot be so 
thoroughly masticated and the fibres so well separated. 
Therefore, veal is not as digestible as beef, nor lamb as 
mutton. " Young flesh is less stimulating and nutritious 
and more gelatinous than that of the adult.' ' (Vaughan.) 
Yeal should not be too pale, as that indicates ante-mortem 
bleeding or too young an animal. The calf should be at 
least one month old before the killing. 



230 A MANUAL OF HYGIENE AND SANITATION. 

Mutton is more digestible than beef, but not so nutri- 
tious. Its flavor is objectionable to some. Pork is an 
economical food for the poor man, as good pigs store up 
three times as much of the food they eat as does the ox. 
The flesh is also easily preserved by drying or smoking, 
and ham and bacon are exceptions to the rule that dried 
meats are more indigestible than fresh ones. Again, pork 
fat furnishes much heat for cold weather by its oxidation 
and combustion in the body. But it must be remembered 
that it requires good digestive apparatus to dispose of it, 
and that much pork is not to be advised for those of sed- 
entary habits ; also that certain parasites are especially 
liable to infest the tissues of the pig and to be transmitted 
thence to man. 

The flesh of poultry is acceptable to most palates, if not 
too old and tough. White meat is more digestible than 
the dark, but not so nutritious or rich in flavor, since the 
latter is more highly nitrogenous. Chicken broth is more 
nutritious and more laxative than that made from mutton. 

Fish is not sufficiently stimulating to constitute the 
chief flesh diet of a people, but it furnishes variety, and 
undoubtedly should be used largely by those subject to 
neurosal affections on account of its contained phosphorus. 
AVhite-meated fish are more delicate in flavor and more 
easily digested, but not so stimulating as those of red flesh. 
Some fish are poisonous, either by nature or from inhabit- 
ing foul waters ; while any fish may become so if under- 
going decomposition. Shell-fish are particularly liable 
to develop poisonous ptomaines in the process of decom- 
position, and, consequently, only such as are absolutely 
fresh should be used. Oysters and clams which have 
been taken from a water contaminated by sewage may 
also convey the germs of infectious diseases, such as 



FOOD. 231 

typhoid fever ; an instance of this having been proven 
in the case of an epidemic of the latter disease in Con- 
necticut, which was investigated and reported by Prof. 
Conn, of Wesleyan University. 

" The following meats [should not be eaten : 1. The 
flesh of all animals dead of internal diseases, or which 
have been killed while suffering from such diseases, or 
animals killed by overdriving. 2. The flesh of animals 
with contagious diseases that may be transmitted to man. 
3. The flesh of animals that have been poisoned. 4. The 
flesh of animals with severe infectious diseases, as pyaemia, 
etc. 5. Flesh that contains parasites that may be trans- 
mitted to man. 6. All putrid flesh/' (Gerlach.) 

Competent inspectors should be and are appointed by 
Government and State authorities to examine the various 
meats offered for sale in large cities, and undoubtedly do 
much good in preventing the sale of meat that is unfit 
for use. Unfortunately, from false ideas of economy in 
many communities, the authorized inspectors are too few 
in number to be able to attend to all the work that is 
required of them. 

Coplin and Be van give the following as diseases which 
are to be specially guarded against, and also discuss the 
symptoms of these maladies and the appearances they 
produce in the flesh and viscera of animals killed while 
suffering from them : In cattle, epidemic pleuro-pneu- 
monia, foot- and mouth-disease, contagious typhus, an- 
thrax, tuberculosis, actinomycosis, Texas fever, dropsical 
affections, and indigestion. In sheep, braxy, variola 
ovina, black quarter, phthisis, fluke disease, and gid. In 
swine, anthrax, hog cholera, measles, and trichiniasis. 1 

1 Manual of Practical Hygiene, 1st edition, p. 132 et seq. 



232 A MANUAL OF HYGIENE AND SANITATION. 

It should also be remembered that the intestinal para- 
sites, such as tape-worms and round-worms, often, if not 
usually, gain entrance into the system through the inges- 
tion of meat containing them in their embryonal or larval 
stages. 

Therefore, in cooking meat, every part should be heated 
to at least 160° F. to destroy any disease germs or parasites 
it may contain, as very rare meat may still harbor these 
organisms in a living state. Tuberculosis, for instance, 
may be incurred by eating flesh imperfectly cooked, since 
its germs are hard to kill ; though it must be said that 
this disease is not so likely to affect the muscular tissues 
of an animal as are others of the maladies mentioned. 
The development of ptomaines in flesh may also make it 
very poisonous, and this is especially likely to occur in 
meats that have been kept for a long time after killing 
or in those preserved in cans or other packages that have 
been imperfectly heated or sealed. 

Meat is also cooked to improve it in appearance and to 
make it more agreeable to the palate and digestion. As 
already stated, the effect of cooking upon muscle tissue is 
" to loosen the bundles of fibrillar from each other so that 
they are readily torn asunder or crushed by the teeth." 
Perfectly cooked flesh is more savory than when it is 
either underdone or overdone. Meat cooked before rigor 
mortis sets in may be tender ; cooked during the rigor, it 
is tough and is masticated with difficulty ; after the rigor 
is past the meat becomes tender again when cooked, pro- 
vided it was so originally. 

In cooking meat, the ultimate condition in which we 
wish it to be should always be kept in mind, and pains 
should also be taken not to overcook or use too high a 
temperature. The processes pursued in making a good 



FOOD. 233 

soup or broth, and in cooking meat so that it may retain 
all its juices, salts and flavors, are radically different. In 
the first case, it is desired to extract as much' of the soluble 
constituents of the flesh as possible, and to do this the meat 
should be cut into small pieces and allowed to remain for 
a time in cold water, this afterward being very gradually 
raised to a temperature of about 160° F. Tn this way 
the juices exude and the salts and soluble parts of the 
meat are dissolved before the pores are closed by the 
coagulation of the albumin. 

On the other hand, if it is desired to retain the juices 
and savor in the meat, the piece should be as large as pos- 
sible, that the surface exposed will be small in proportion 
to the volume. The piece is then to be first subjected to 
a temperature as high as possible, that the surface may be 
cooked at once and the albumin coagulated, the juices 
being thus prevented from escaping by the sealing of the 
pores. In boiling this end is attained by plunging the 
meat at once into boiling water; in roasting, by having the 
fire or oven very hot. After this first heating it is best to 
diminish the degree of heat somewhat, that the subsequent 
cooking of the interior may go on more slowly and the 
temperature within may not rise above the coagulating- 
point to make the fibres hard and stringy. Meat cooked 
in this way should be tender, juicy and full of flavor. 
Broiling or grilling is, of course, but a modified roasting. 

Soups and broths made of meat juices alone and with- 
out the addition of other substances are stimulating rather 
than nutritious, as they contain little albumin, carbohy- 
drates or fat. However, if certain vegetables be added 
to the soup, the latter will gain sufficient of these food- 
principles and be highly nutritious, and such vegetable 
soups are of great value in all schemes of economic cooking. 



234 A MANUAL OF HYGIENE AND SANITATION. 

Bones are also of value on account of the salts, gelatin 
and other soluble organic matter which they contain, and 
used with vegetables they make especially nutritious and 
easily digested soups. 

The meat from which soup has been made, on the other 
hand, is not all that is desirable, for though it still con- 
tains albumin and fat, it has lost its salts and savoriness 
and is unpalatable and, therefore, not easily digested. It 
needs something — a sauce or condiment, or preferably a 
meat extract, for meat extracts are nothing but thin soups 
evaporated to dryness or condensed. Or, if both soup 
and the meat be taken at the same meal, the things lack- 
ing in each are supplied in the other, and the needs of 
digestion and nutrition are supplied. 

Frying meat, as it is commonly practised, should not 
be condoned or tolerated, as it renders the albumin of the 
flesh extremely tough, beside soaking it with fat or grease 
and thus greatly increasing the difficulty of its digestion. 
But frying by total immersion in boiling fat is an excel- 
lent way of cooking meats containing much water, and 
especially fish, for the boiling-point of fat or oil is very 
high and the meat is instantly cooked on the outside, 
while the water in the interior, being converted into 
steam, prevents the ingress of fat by its expansion, cooks 
the albumin, and leaves the flesh in a light, flaky condi- 
tion. But the fat must be boiling hot when the meat is 
immersed, and the latter must not be allowed to remain 
in the former longer than just suffices for the perfect cook- 
ing. 

Beef- tea as ordinarily made is only a thin extract of 
beef, the stimulating properties of which will be consid- 
ered hereafter. To make a beef -tea containing any con- 
siderable amount of nutriment, the meat from which the 



FOOD. 235 

juices have been extracted should be dried, pounded fine, 
and all fibrous and tendinous portions should be removed. 
This pounded beef should then be added to the liquid ex- 
tract, as then only is it really a food. However, the 
mixture should always be seasoned, even for the sick, 
that it may be thoroughly acceptable to both palate and 
stomach. In making the extract, remember that the 
meat should be cut into very small pieces and added to 
cold water in about the proportion of one pound of lean 
meat to one pint of water, and that the whole should be 
brought to the boiling-point very slowly. 

The cereals form one of the most valuable kinds of 
food. All but rice contain considerable proteid matter — 
from 10 to 20 per cent. — beside carbohydrates, which pre- 
dominate, some fat and a goodly proportion of phosphates. 
Rice has only 5 per cent, of proteids to 75 per cent, of 
starch, but it is easily digested and is, therefore, a valu- 
able food for the youug and the sick ; it is also well fitted 
as a chief food for dwellers in hot climates on account of 
its low heat production. 

Wheat is the most nutritious cereal, and bread made 
from it is aptly called " the staff of life," since it is a 
food which, with the addition of a little extra fat and 
albumin, furnishes the essentials in proper proportion for 
the support of life. Barley closely resembles wheat in 
composition, and rye also is rich in nutriment, though 
perhaps a little more difficult of digestion than wheat. 
Oats are valuable on account of the large amount of fat 
they contain — over 5 per cent, beside a full share of 
proteids, starch and salt. But ordinary oat-meal needs 
vigorous digestive functions and, where the latter are 
lacking, it is often productive of intestinal disturbance 
and irritation. Corn or maize, though not a true cereal, 



236 A MANUAL OF HYGIENE AND SANITATION. 

f urnisbes a valuable food with considerable fat ; it also 
contains a vegetable fibrin. The proteid constituents of 
the cereals are vegetable albumin, casein and gluten, the 
last of these being most abundant in wheat and, perhaps, 
of the highest food value. 

Grinding breaks up the grain and the starch granules 
of the cereals, aids in separating indigestible parts, and 
renders the starch much more suitable for cooking. 
Wheat flour ground by the old method should be soft and 
smooth, but that made by the new roller-process is more 
apt to be slightly granular. It should not be too white, 
as that indicates a lack of the proper proportion of gluten, 
and should contain everything but the outer husk of the 
grain. The inner coats should be retained in the flour, 
as they hold a good part of the gluten and practically all 
of the grain salts. Corn-meal should be dry and pow- 
dery, or, at least, not too granular. Flour of any kind 
should be kept well covered in a dry place, and should 
contain no living organisnis nor any adulterants. 

Bread is practically made of flour, water and salt, 
though sugar, milk, etc., may be added to improve the 
flavor. As flour and water alone make a tough and in- 
digestible mass, bread is leavened to make it easier of 
mastication and digestion, and for this purpose either 
yeast, baking-powder or aeration is employed. Yeast at 
the proper temperature rapidly converts the starch or 
sugar into carbonic-acid gas and alcohol, the former of 
which in escaping makes the dough porous and light, the 
walls of the cavities it produces being kept from collapsing 
by the tenacity of the gluten until the heat has fixed them 
permanently. As the heat of baking dissipates both the 
gas and alcohol, from 10 to 12 per cent, of the weight of 
the flour used is lost by this method. Moreover, if the 



FOOD. 237 

fermentation goes beyond a certain point, lactic and acetic 
acids are formed and the bread becomes " sour." Con- 
sequently, it has been advised that the yeast method be 
discarded and that the leavening be done by means of 
baking-powders or aeration. Carbonic-acid gas is evolved 
from the baking-powders upon the application of heat and 
moisture, and the bread is made light by the gas, with no 
loss of food-substance, and, if the powders are pure, with 
nothing harmful added to the bread. There should be 
no alum or other adulterants in baking-powders, any 
more than in the flour itself. Alum unites with the 
phosphates of the flour, rendering them insoluble and 
preventing their absorption from the alimentary tract. 
Bread may also be leavened on a large scale by forcing air 
or carbonic-acid gas under high pressure into the dough, 
or by mixing the flour with cold water heavily charged 
with the latter gas. In this method, also, there can be 
no loss of food material nor any detriment to the bread, 
provided cleanly precautions are observed. 

Good wheat bread should be almost white, light, sweet, 
spongy, and with a crust easily broken and equal in bulk 
to about one-quarter of the loaf. As considerable of the 
starch has been converted into dextrine in the crust, the 
latter is more easily digested than the interior of the loaf. 
Fresh bread is not nearly so digestible as that which is 
a day or two old. As stated, bread needs only a little 
added fat and albumin to make it a perfect food, the 
former of which, at least, is almost if not quite sufficiently 
supplied in the butter which we commonly use upon it. 

The vegetables in common use are valuable articles of 
food, in that they give us the larger portion of our car- 
bohydrates and also furnish an agreeable variety from day 
to day. In the fresh state they contain considerable 



238 A MANUAL OF HYGIENE AND SANITATION. 

water — from 75 to 90 or 95 per cent. — the residue being 
mainly one or the other of the carbohydrates. Potatoes 
exemplify this well, since they contain but little proteids 
and fat, and practically all of their solid matter is starch. 
On account of their customary cheapness and ease of 
growth and storage they are usually considered to be a 
good article of food for the poor man, but it should not 
be forgotten that other foods which are apparently more 
expensive may at times be actually cheaper than potatoes, 
both on account of containing those principles which the 
latter lack and because they may require less expenditure 
of digestive energy. (See chart, page 241.) Beets contain 
much sugar and are nutritious, palatable and easily di- 
gested. Onions have considerable sulphur and should be 
used freely when its need is indicated. Cabbage, cress and 
other greens are especially valuable for the organic salts 
which they contain, and because they serve so well as rel- 
ishes. Spinach is said to contain more assimilable iron 
than any other article of fQod commonly used. Celery and 
lettuce are nerve sedatives, and asparagus acts as a diuretic 
and is thought to be of special benefit to the kidneys. 

The seeds of the leguminous group of plants, such as 
peas, beans, lentils, etc., contain from 22 to 25 per cent, 
of proteid matter in the form of vegetable casein, and 
almost 50 per cent, of starch. It is on account of this 
abundance of food-matter that they make such a valuable 
addition to soups and the like, and for the same reason 
they should also be considered and used in any dietary 
where economy of expense is to be a factor. Green peas 
and beans are much more digestible than those that have 
ripened and dried, though, of course, they do not yield as 
much food, weight for weight, as the latter. 

All vegetables should be cooked so as to retain their 
salts, or else the water in which they are cooked and 



FOOD. 239 

which contains these salts should be used in making soup 
or broth, to be served at the same meal with the vege- 
tables. This is especially advisable with regard to pota- 
toes and sweet potatoes, as their soluble salts have much 
to do with their digestibility. It is for this reason that a 
properly roasted potato is always better than a boiled one, 
and that steamed vegetables are both more palatable and 
more digestible than those which have been cooked under 
water. In fact, Mattieu Williams has even suggested 
that possibly one reason why gout is so prevalent among 
Englishmen is because they habitually eat boiled vege- 
tables and throw away the water in which these have been 
cooked. The salts not only help in the digestion of the 
starches, but they furnish bases to unite with and render 
soluble (he irritating acids that produce the gouty symp- 
toms. It should also be remembered that the dried 
legumes should always be softened by soaking before 
cooking, and that they as well as other vegetables should 
be cooked, whenever possible, in soft water. 

Fruits are especially valuable on account of their flavor, 
acceptability to the palate, benefit to the digestion, and 
for their laxative action. Ripe fruits may be eaten freely, 
but in most cases, preferably early in the day. Fresh 
fruits are usually better than those dried or otherwise pre- 
served ; but where the former cannot be had, the latter 
should be used freely, and all should be used whenever 
possible throughout the year. Green fruit, or that which 
has begun to decay, should not be eaten, for obvious 
reasons. 

Nuts are nutritious on account of the high percentage 
of fat that most of them contain, but are difficult of diges- 
tion unless carefully masticated. Recently pastes made 
from various nuts have been placed on the market, and 
are to be considered as an agreeable addition to our 



240 A MANUAL OF HYGIENE AND SANITATION. 

dietaries. Prepared starches, such as arrow-root, tapioca, 
sago, etc., are very digestible and, therefore, useful, espe- 
cially in the preparation of food for the young or the sick. 

Much may be written concerning the adulteration and 
sophistication of food-stuffs and of the addition of more 
or less harmful preservatives to food of a perishable 
nature. That the first is carried on to an enormous extent 
seems certain. The remedy appears to be in the passage 
and enforcement of stringent laws and the maintenance of 
frequent and rigid inspection by both State and govern- 
mental authorities, in the dissemination of information as 
to the adulterations practised and the means of detecting 
them, and in the utmost publicity and exposure in the 
case of transgressors. 

As to the use of preservatives, the very extensive sale 
of these in localities where they would be most likely to 
be added to food indicates their employment, as does their 
continual discovery by direct analysis. In Birmingham, 
England, such preservatives were found in 20 per cent, 
of 2300 samples of food examined, and boric acid in 5 
per cent, of 1360 samples of milk. Such substances as 
boric acid, salicylic acid and formaldehyde are commonly 
used, though it is frequently stated that more dangerous 
ones, such as hydrofluoric acid, are occasionally employed. 
And though it should in fairness be stated that it is pos- 
sible that, if only the minimum of such substances as boric 
acid or formaldehyde necessary to prevent putrefactive or 
fermentative changes in food be used, no harm to the 
human economy will result, 1 yet it is undoubtedly wiser 

1 Rideal and Fullerton (Public Health, May, 1899) arrive at the following con- 
clusions : 1. Boric acid (1 to 2000) and formaldehyde (1 to 50,000) are effective pre- 
servatives for milk for twenty-four hours. 2. These quantities have no appreciable 
effect upon the digestion. 3. These quantities have no appreciable effect upon 
the digestibility of foods prepared by them. 4. Formaldehyde in the proportion 
given above, so far as our investigations have extended, does not appear to have 
any injurious action upon animal tissues or nutrition. 



FOOD. 



241 



to condemn entirely the practice of adding chemical pre- 
servatives of any kind to food. There are two reasons 
for this: 1. There is no surety and very little proba- 
bility that the minimum quantity of preservative consistent 
with safety to health will not be exceeded in most cases 
through carelessness or recklessness. 2. That foods that 
need such preservatives should be supplied to the con- 
sumer before the deterioration in them has begun, or else 
they should be sterilized by the more costly but safer 
employment of heat. 

The following diagram may be of service to some in 
determining the value of certain food-stuffs : 

Fig. 42. 




CHAPTEK VII. 

STIMULANTS AND BEVERAGES. 

The essential function and property of stimulants is to 
liberate some of the latent force of the body, and they are 
of use and value in sudden emergencies, to tide the system 
over important crises, to hasten a tardy convalescence, 
or, perchance, to whip up a flagging digestion so that it 
may the better prepare food for the repair of waste or 
the supplying of body-fuel. Those stimulants, excluding 
drugs, with which we are most concerned are of three 
classes, viz., nitrogenized vegetable stimulants, such as 
tea and coffee ; nitrogenized animal stimulants, as beef- 
tea and meat-extracts ; and alcohol. All these are u force- 
liberators/ 7 and, though alcohol may sometimes act the 
part, in more moderate measure, of a u force-producer," 
it is well to remember that they scarcely give anything at 
all to renew or replace the energy which they set free. 

This being so, care should always be taken that some 
food may be supplied during or shortly after the stimula- 
tion produced by the agents in question, in order that the 
body may have a new store of force to replace that which 
has been liberated. Especially is this necessary in cases 
of sickness, and as the soluble carbohydrates furnish fuel 
and consequent heat and energy to carry on the vital pro- 
cesses, these even more than other kinds of food are to be 
supplied and will generally be well received and utilized 
by patients or others in need of stimulation. Again, just 
as we must not depend on stimulants alone to the exclu- 



STIMULANTS AND BEVERAGES. 243 

sion of food, so also must we take care not to continue 
their use any longer than is necessary to attain our object, 
and likewise must not over-stimulate or carry the action 
so far that the body is left poorer and weaker in force 
than before the use of the stimulants began. 

For example, beef-tea constantly stimulates the vital 
and nervous functions to greater activity, this requiring 
that either tissue or food be oxidized to produce the neces- 
sary energy. The stimulating factors in ordinary beef- 
tea are the extractives, such as kreatin and kreatinine, 
which are the products of the wear and tear of life, inter- 
mediate between living, active tissue and the final excretory 
matters, such as urea and uric acid ; hence, they can have 
little, if any, real food value. Beside these the beef-tea 
contains only the salts of the meat, which, though valu- 
able, are not force-producers. Therefore, unless food be 
otherwise supplied, the body-tissue must be consumed, and 
the result must be in the end disastrous ; and yet this is 
what occurs to many patients through the mistaken idea 
that beef-tea is both nourishing and stimulating. When 
" whole beef-tea " (the recipe for which has already been 
given on page 235) is used these remarks do not apply, 
since it contains some true food, though even here soluble 
or readily digestible carbohydrates may be wisely added. 

The active principles of the nitrogenized vegetable 
stimulants resemble very closely in chemical composition 
not only the meat extractives, but also those drugs, like 
strychnine, which are used in medicine as tonics and 
cerebro-spinal stimulants, and they act physiologically in 
a similar though milder manner. 

A.s beverages, tea, coffee and cocoa supply fluid for the 
system and that stimulation of the assimilative functions 
that gives the sense of comfort after their use ; cocoa and 



244 A MANUAL OF HYGIENE AND SANITATION. 

chocolate having also the advantage of supplying some 
food. But these beverages can all be abused in their 
use as readily as can beef- tea or alcohol, and li tea-drunk- 
ards or coffee-drunkards " are not uncommon in our hos- 
pitals or in private life. The teacup is not always the 
one that " cheers but does not inebriate." Women espe- 
cially who drink much tea are apt to be nervous and 
dyspeptic, to have the " tea-drinker's heart/' and to suffer 
from headaches and neuralgias. They depend upon tea 
to take the place of nutriment, and soon use up what 
little store of force they may have had, since they fail to 
replenish it with new fuel-food. 

Men are more addicted to the use and abuse of coffee, 
aud often manifest symptoms directly traceable to it. 
While caffeine increases heart action, and may be used to 
advantage in cases of cardiac debility, for the same reason 
it should be taken with caution and in moderation where 
the cardiac action is already too vigorous Vogel has ad- 
vised the use of strong coffee with sugar and cream as a 
tonic and food in debility accompanying the acute diseases 
of children. 

It is interesting to note that among all nervous, 
energetic people the use of some one or other of these 
stimulant beverages is common, and that " total ab- 
stainers " from alcohol seem instinctively to take to tea 
or coffee. And while it is probably theoretically true 
that the healthy person would better abstain entirely from 
the use of stimulants, except in emergencies or at rare 
intervals, yet this almost universal demand and use of 
them probably indicates that under our present high ten- 
sion of living there is a practical physiological demand 
and need for them that perhaps should be satisfied in a 
measure, but with moderation and judgment. 



STIMULANTS AND BEVERAGES. 245 

Alcohol. Liebig says c< alcohol stands only second to 
fat as a respiratory material," but adds that " the same 
effect could be produced in the body by means of saccharine 
and farinaceous articles of food at one-fourth or one- fifth 
the cost." Fothergill also holds " that the chief portion 
of the alcohol ingested undergoes consumption in the 
body," but insists that " the question of ' alcohol as a 
food ? can never be separated or divorced from that of 
[ alcohol as a stimulant ' or as a force-liberator." 

Much undue importance has recently been given to 
some scientific investigations that have served to establish 
the fact that alcohol can be and often is almost completely 
oxidized in the body, and that it produces therein prac- 
tically the same number of heat units as when it is con- 
sumed outside. But the inference that it can therefore 
be substituted for and used with impunity in place of the 
usual carbonaceous foods is not justifiable, because the 
powerful physiological and ultimate pathological effect 
of the alcohol upon the higher nerve-centres and active 
tissues is ignored ; because of the liberation of the body's 
latent force in excess of that which the alcohol supplies, 
and because even the above-mentioned investigations and 
experiments went to show that there was an actual detri- 
ment to the nitrogen-bearing tissues of the body during 
its use. 

Again, Liebig writes that " the use of spirits is not 
the cause but the effect of poverty. It is the exception 
to the rule when the well-fed man becomes a spirit-drinker. 
On the other hand, when the laborer earns by his work 
less than is required to provide the amount of food which 
is indispensable in order to restore fully his working 
power, an unyielding, inexorable law or necessity compels 
him to have recourse to spirits. He must work ; but in 



246 A MANUAL OF HYGIENE AND SANITATION. 

consequence of insufficient food, a certain portion of his 
working power is daily wasting. Spirits, by their action 
on the nerves, enable him to make up the deficient power 
at the expense of his body ; to consume to-day that quan- 
tity which naturally ought to have been employed a day 
later." This may also be the case where there is an 
abundance of food, but where it is improperly chosen for 
the needs of the individual or ruined in the preparation 
by bad cooking. Education in the principles of the scien- 
tific and economical selection of food and its preparation 
may thus become a means of preventing those diseases that 
depend on or are aggravated by insufficient or improper 
food and consequent alcoholic excesses. The effect of 
alcohol upon the weak and savage races is much more 
marked and disastrous than upon the civilized and strong j 
so it harms the health of the underfed and overworked 
much more than it does that of the well-fed man of means 
and leisure, and affects women and children more than 
adult men. This latter Jpoint is to be remembered in 
practice. 

Remember also that, while alcohol is partially a respira- 
tory stimulant, it is a force-liberator and consumes the 
body store, and unless given with other readily oxidizable 
food the risk is run of putting a patient "in a grave 
never dug by Nature/' especially where there is already 
danger of the patient sinking from exhaustion. But it is 
just in these cases, when given with other food, that we 
find alcohol a valuable therapeutic agent. Give it with 
foods that produce heat and force — i. e., some form of 
the soluble carbohydrates, as maltose, malt extracts, milk, 
milk-whey, or even sugar. Where the assimilative powers 
are weak it may be advantageous or necessary to par- 
tially or wholly predigest these foods ; but above all, 



STIMULANTS AND BEVERAGES. 247 

remember to replace what alcohol takes from the body, 
or physiological bankruptcy will ensue. Note also that, 
though alcohol may be in one sense a food, it is a very 
costly one, and that intoxication must occur long before 
a man could get the equivalent of a full meal. 

Alcohol is to be used in sickness practically to sustain 
the vital powers, to meet emergencies, and to lift the 
patient over obstructions in the road to health ; and such 
use requires a thorough knowledge of its action coupled 
with the highest judgment. 

In malt liquors there is considerable maltose left un- 
changed, thus combining with the alcohol a soluble carbo- 
hydrate of the highest value, and these brewed ales, etc., 
may often be used with benefit as tonics, especially where 
convalescence is prolonged. The stronger distilled liquors 
are diffusible cardiac stimulants, and are especially valu- 
able in emergencies, but the continued use of them must 
only be advised with great caution. Fothergill gives two 
excellent rules for the use of alcohol by the healthy : 
r First, never have alcohol in the brain when it has work 
to do ; second, a little alcohol betwixt a man and past 
trouble is permissible ; but it is not well to put a little 
alcohol in front of a coming trouble.' 7 Murchison, in his 
work on Fevers, lays down these rules for practice, which 
it would be well for all to adopt : " What are the con- 
ditions of the animal economy in which alcohol may be of 
positive use ? That there are such conditions, I believe 
cannot be denied by any one who has honestly studied the 
subject ; but they are not the conditions of perfect health. 
It is especially when the circulation is weak or sluggish 
that a daily allowance of alcohol may do good. Thus : 1. 
Alcohol is useful in the course of most acute diseases, 
when the organs of circulation begin to fail, as they are 



248 A MANUAL OF HYGIENE AND SANITATION. 

apt to do. A moderate quantity usually suffices. The 
large quantity still sometimes administered may do harm 
by inducing congestion of internal organs. 2, In con- 
valescence from acute diseases, or from weakening ail- 
ments, when the circulation remains feeble and the 
temperature is often subnormal, alcohol is useful in pro- 
moting the circulation and assisting the digestion. 3. In 
persons of advanced life the circulation is also often feeble, 
and a moderate allowance of alcohol often appears to be 
beneficial. All other conditions of the system marked by 
weakness of the muscular wall of the heart, whether per- 
manent or transient, are usually benefited by alcohol." 
Alcohol is a good servant, but a bad master. King 
Chambers says : u Let alcohol be taken never as a stimu- 
lant or preparative for work, but as a defence against 
injury done by work, whether of mind or body. For 
example, it is best taken with the evening meal or after 
toil. Let the increase in the desire for and the power of 
digesting food be the guide and limit to the consumption 
of all alcoholic liquids. Let the forms be such as contain 
the least proportion of fusel oil. Let all with an heredi- 
tary tendency to hysteria or other functional diseases of 
the nervous system refrain from its use altogether, even 
though as yet in good health. " 

Beverages. 

To comment individually upon the multitude of non- 
alcoholic and non-stimulating beverages that are now 
more or less generally used, is both impracticable and un- 
necessary, nor will any attempt to classify them be of 
much value. For the most part they serve only to please 
the palate ; though if in this way they bring about a 
greater ingestion of fluids when these are needed, their 






STIMULANTS AND BEVERAGES. 249 

service cannot be considered a vain one. For it has 
already been stated that an ample supply of drinking 
water or other fluids taken daily and habitually is essen- 
tial to the satisfactory removal of the various waste mat- 
ters from the body, and that without it the latter may 
readily develop conditions favoring disease. 

Moreover, it is true that certain gases and salts held in 
solution in some beverages, such as mineral waters, in- 
crease this excretory action, and may be highly beneficial 
in appropriate cases ; but it should be a matter of caution 
that where such therapeutic results are thought to be neces- 
sary, competent medical advice should be the guide as to 
the kind and quantity of the agents used. This comment 
is justified by the fact that of late many substances pos- 
sessing decided physiological power have been advertised 
and sold in the form of one beverage or another directly to 
the laity, who, being incompetent to judge as to whether or 
not such substances are actually needed in their individual 
cases, may actually do themselves much harm in this way. 

Only such beverages, then, as are quite simple in their 
nature or as are advised by competent medical authority 
should be used. If they are artificially made and water 
is the solvent fluid, as it will be in most cases, there 
should also be certainty that it comes from a clean and 
safe source, lest it carry the germs of disease. There is 
no doubt that frequently the cheaper bottled drinks which 
are dispensed so generally are made from water that has 
been liable to more or less dangerous pollution, and there 
is the additional risk that arises from the imperfect cleans- 
ing of the bottles for these liquids which have been re- 
turned to be refilled. A little thought as to the dangers 
which do exist in relation to this matter will be convinc- 
ing as to their gravity. 



250 A MANUAL OF HYGIENE AND SANITATION. 

Many of the most popular beverages are highly charged 
with carbonic-acid gas under pressure, and the fact that 
so much of this gas can be taken into the system in this 
way without apparent harm, and its free elimination, 
would seem to be additional evidence that it cannot in 
itself be so very harmful in the atmosphere, even when 
in proportions considerably greater than the normal. 

In conclusion, it may be said that a free use of all such 
beverages as are known to be clean, safe and wholesome 
will probably be found to be entirely favorable to health, 
unless there be some contraindicating reasons .peculiar to 
the individual himself ; and that their substitution, when- 
ever possible, in place of the alkaloidal and alcoholic 
stimulants is to be commended on hygienic as well as 
other grounds. 



CHAPTER VIII. 



PERSONAL HYGIENE. 



The proper consideration of this subject demands an 
ample volume rather than the limits of a single chapter, 
for the ultimate aim of all sanitary work is the preserva- 
tion and betterment of the health of the individual, and 
beside, the factors that affect the well-being of the person 
are so multitudinous in their number and in their phases 
that no brief discussion can comprehend them all. 

However, much that pertains to personal hygiene and 
that requires no repetition for its application has already 
been given in the preceding pages ; so that it is hoped 
that if the reader will exercise that virtue of common-sense 
and reflection that is so essential in this study, the remarks 
to be added will be helpful in suggestion and in answer- 
ing many questions, even though they may not be consid- 
ered in any way as complete discussions of the respective 
themes. 

Each age has its own requirements, and that which 
may be entirely satisfactory or permissible at one time 
may not be so at another. To attain the best results it 
will often be necessary to even anticipate with prophylactic 
measures the birth of the child ; and broadly speaking, 
much of the welfare of future generations lies in the care 
of those now living. 

One of the gravest sociologic problems of the day is as 
to how far the State is justified in restricting or preventing 



252 A MANUAL OF HYGIENE AND SANITATION. 

the propagation of the defective or degenerate of the 
human race ; and though the time may not yet be ripe for 
the law to take positive action in these matters, it is the 
duty of every sanitarian to use his utmost efforts to the 
end that only the healthy and the normal may continue. 

The advances in physiological and biological science in 
recent years have done much for all humanity, but in no 
respect, perhaps, have they been of more service than in 
determining the great influence of environment and in 
establishing the fact that the presence or absence of disease 
is oftentimes, if not always, due as much to the predis- 
posing conditions and physical status of the individual as 
to external and exciting causes. What may cause only a 
trifling ill in one may bring about most serious evils in 
another whose environment is not so fortunate. 

Life has been defined as the power of an organism to 
continually adjust its internal conditions to its external 
conditions, and as long as this is done satisfactorily life 
persists. The secret of personal hygiene and health, then, 
must lie in determining the relationship between the in- 
ternal and external conditions of the individual's organism. 

" Know thyself " is advice good for the body as well 
as for the mind or soul, and knowledge of the right kind 
can do no harm. He who knows his personal and physi- 
cal nature and acts accordingly is well equipped to fight 
against the ills of life, and the study of the relationship 
above referred to will help the thinking man so to care 
for himself that in all probability his days will be pro- 
longed. 

But a caution or two must be interpolated here. It is 
well known that " expectant attention " too persistently 
directed toward a certain organ may lead to decided altera- 
tions or disturbances in the functions of that organ ; and 



PERSONAL HYGIENE. 253 

again, unless one well understands the mysteries of human 
physiology, a little imperfect or insufficient information 
in this respect may lead to the assumption or pursuit of 
habits and practices actually dangerous to health. Too 
much ill-advised care and attention may be just as full of 
risk as too little, and physiological egotism without a 
sound basis may have a bitter reward. 

What is needed is that each one should study carefully 
the phenomena of his daily life, should determine care- 
fully and accurately the purpose and reason of each of the 
respective functions, and then, not forgetting their mutual 
interdependence upon one another and that all should 
work in harmony, should endeavor to do that which will 
best facilitate the functional activity with the least ex- 
penditure of energy. 

There are a number of ways in which the study of per- 
sonal hygiene may be advantageously pursued, but for 
practical purposes one of the best is to consider it with 
respect to the main groups of organs and functions of the 
body, keeping always in mind, however, the correlation 
of these and that no part of the body can be entirely in- 
dependent of the rest. 1 Nevertheless, the hygiene of in- 
fancy is a study by itself, for it is in that epoch of life 
that the plastic constitution can be and is moulded most 
readily by all the influences of the environment, whether 
for good or evil, and it is at that time that salutary efforts 
are to be made with most hope of success and eventual good. 

Moreover, the principles of personal hygiene may be 
more readily taught to and inculcated in the young, but 

1 This method has been followed in Pyle's Manual of Personal Hygiene, to 
which the reader is referred for an admirable discussion of the subject, which 
must be treated all too briefly here. The writer would also recommend Starr's 
Hygiene of the Nursery to all who desire specific and authoritative information 
concerning the young. 



254 A MANUAL OF HYGIENE AND SANITATION 

with much greater difficulty can we affect the mature or 
aged ; for we are all creatures of many habits, and in the 
mature adult the impress of these may resist to the utmost 
any and all endeavors to modify or remove them. 

Too much stress cannot be laid upon the fact that it is 
the constitution, the nature of the inherent tissue, that 
controls or modifies the inception of many of the ills of 
life, and that whether this in its normal and highest vigor 
be a bequest of heredity or be only altained by the most 
careful attention to details in the practice of the art of 
hygiene, it should always be looked upon as the most 
valuable physical possession of the individual. 

To quote what has already been written : " The essence 
of sanitation is to secure perfect health, to increase the 
inherent power to resist noxious and harmful influences, 
and to make all the surroundings and environments of the 
body pure and free from depressing factors.' ' 

With this preface, the following discussions are added 
in the hope that they may be of some assistance in deter- 
mining the way of right living and in securing the welfare 
and health of every individual. 

Heredity. 

In the broadest sense heredity is a characteristic jointly 
possessed by two cells, furnished by respective parents, 
which join and form a fused cell, which carries on its 
evolution under certain governing impressions indelibly 
stamped by the two parental lines of descent ; but, in the 
ordinary use of the term, it may be defined as the trans- 
mission to the offspring from parent or ancestor of a trait, 
type, temperament, characteristic, or predisposition which 
has a governing or influencing effect upon the growth or 



PERSONAL HYGIENE. 255 

nature of that offspring. This transmitted impression 
may be either for good or for evil. 

" It shows an incorrect conception of the law of hered- 
ity to look for a return of identical phenomena in each new 
generation/' 1 Also, "we do not mean exclusively by 
heredity the very complaint of the parent transmitted to 
the children, with the identical symptoms, both physical 
and moral, observed in the progenitors. By the term 
heredity we understand the transmission of organic dis- 
positions from parents to children. 772 

Consequently, as hygienists, we must use the influence 
and power that we have to further the transmission of 
beneficial or elevating characteristics only, and to prevent 
the bequest of harmful influences and hereditary diseases 
to the generations to come. " The germ of the unborn 
infant must be complete and untainted in all its nature, 
otherwise we cannot hope for a vigorous and perfect 
growth or development. 77 

As the family is the foundation of the State, and society 
is a congregation of men for the purpose of acquiring 
greater power and more comforts through mutual co-opera- 
tion, the latter, whether domestic or civil, has some right 
to make men understand that they must care for the health 
of the generations to follow, and to enact just laws looking 
to the prevention or obliteration of transmissible infirmi- 
ties. And history seems to show that no great nation has 
ever been destroyed or overwhelmed until its people had 
first neglected or abused the laws of hygiene, heredity 
and sociology. 

We find that a married couple have generally, beside 
themselves, the welfare of five human beings within their 

1 Moreau : Psychologie Morbide. 

2 Morel ; Traite des Degeuerescences. 



256 A MANUAL OF HYGIENE AND SANITATION. 

keeping. To produce healthy children and ones not prone 
to disease both parents should possess good constitutions, 
and they should take great care not to weaken these by 
excesses of any kind, physical or mental, nor, as far as 
lies in their power, by any chronic disease. It is evident 
that children of parents that have been conscientious ob- 
servers and followers of Nature's laws must have a better 
chance for health and superiority all their lives. 

In this climate the proper age for marriage is consid- 
ered to be about twenty-four or twenty- five for the man, 
and nineteen or twenty for the woman, though this must 
vary with the state of development of the parties concerned. 
Some of both sexes mature at a considerably earlier period 
than do others, and it would be unjust to say that they 
were not fit for the duties of marriage till they reached 
the age of slower-growing ones. Usually, however, before 
the ages given development is not complete and the whole 
organism is in a transition state. We know that the use 
of any organ before it has attained its complete growth or 
development is very apt to cause exhaustion, or perhaps 
premature degeneration of that organ, and we cannot but 
believe that children developed in immature sexual organs 
must be deficient in true vital force and energy. It is 
often noticeable that a child apparently strong and vigor- 
ous may have but little power to resist disease or may even 
be strongly predisposed to some infirmity ; in such cases 
there will likely be some defect or taint in the parent stock. 

Distinguishing characteristics are more apt to be trans- 
mitted in the early married life of parents, because their 
organs and forces are then more vigorous ; but if a couple 
marry when quite young and before their own organs are 
fully developed, their elder children may be more defi- 
cient, mentally and physically, than their later ones. 



PERSONAL HYGIENE. 257 

Late marriages are not likely to be as fruitful as earlier 
ones, possibly owing to the increased difficulty of parturi- 
tion on the part of the mother and her consequent unwill- 
ingness to undergo the ordeal more than a few times. But 
healthy middle-aged persons, who have married late, may 
have even healthier children than those who have married 
too early. 

In features, constitution, sense-organs, shape of head, 
etc., the child is most apt to resemble the father ; while 
it will likely follow the mother in the shape of the trunk 
and in the formation of internal organs. The character 
and mental qualities of the child may come from either 
parent or both. Maternal impressions during pregnancy 
undoubtedly often have a marked effect upon the coming 
infant. 

Hereditary influences are generally transmitted directly 
from parent to child, but we occasionally find a cessation 
of the trait or predisposition for one or more generations 
and then a recurrence. To such a peculiarity we give 
the term atavism. " A family history of less than four 
generations has only a limited value. " 

A disease may be truly congenital — that is, transmitted 
directly from parent to offspring — as syphilis, scrofula, 
etc. ; or there may be only an inherited predisposition to 
the disease, as toward tuberculosis, etc. Physicians have 
thus a twofold duty : first, to do all they can to guard 
against the transmission of such diseases ; second, to com- 
bat the disease or any tendency toward it as soon as any 
symptoms thereof are discovered or it is suspected in the 
child. The first duty can be accomplished, theoretically, 
by preventing generation and production on the part of 
those unfit to produce offspring, and practically, within 
certain limits, by fighting the causes and their effects in 

17 



258 A MANUAL OF HYGIENE AND SANITATION. 

the parent individual, especially at the ages or times when 
these have the greatest force or are most apt to manifest 
themselves. For the second, the child must be imme- 
diately placed in the most favorable hygienic surround- 
ings, and everything possible done to prevent the further 
development of the disease or predisposition. In many 
cases such early interference will accomplish much good, 
and the disease may be averted entirely. Especially is 
this true of those inheriting the tuberculous diathesis. 

Too often the child of a tubercular .parent is kept after 
birth under the same conditions that served to develop 
the disease in the parent, and its inherited predisposition 
to the malady is intensified by the environment of a damp 
and undrained soil, a dark and unventilated house, etc., 
and by insufficient or improper food until infection is all 
too easily acquired, and the child that might have been 
saved becomes an early victim of the ignorance, care- 
lessness or neglect of those who should have fostered 
it with extremest care and solicitude. On the other hand, 
the apparently complete eradication of the transmitted 
predisposition from many children whose inheritance has 
been as bad, but who have been promptly removed from 
the unsanitary environment of their birth, shows how 
much this one influence may work for good. 

The most important of the hereditary or transmissible 
diseases are syphilis, tuberculosis, scrofula, cancer, gout, 
hysteria, epilepsy, certain physical deformities, certain skin 
diseases, insanity, and criminal tendencies of various kinds. 
But do not forget that what may appear to be a direct and 
actual inheritance of a disease may only be the production 
of the disease in that person by the same agents, environ- 
ments and morbid conditions as caused or favored the 
disease in the parent. However, even here there is very 



PERSONAL HYGIENE. 259 

possibly a transmitted predisposition to the acquirement 
of the disease, rendering it all the more easy for it to 
manifest its symptoms upon slight provocation. There- 
fore, there should be no marriage between persons inher- 
iting predispositions to the same disease, especially if they 
be relatives, and " a person affected with hereditary or 
well-marked constitutional syphilis, or having a strong 
consumptive taint, or tendency to mental unsoundness, 
should not marry at all." 

Defective eyesight is very apt to be transmitted to 
children, and the latter should be carefully examined and, 
if necessary, fitted with proper glasses before being placed 
at school or at any work requiring much use of the eyes. 

Infirmities which do not prevent marriage from being 
fully accomplished, or which do not tend to the degenera- 
tion of the offspring, are not good reasons alone for for- 
bidding marriage, but all that have such a tendency are. 
A man should not marry a woman too far advanced in 
life, nor one that is very feeble, delicate or deformed, 
especially as to the chest or pelvis. Hysteria, convul- 
sions and epilepsy due to organic disease should prevent 
a woman from marrying, though some extremely nervous 
and hysterical women are much benefited by marriage, 
and have healthy children. So with many women who 
have uterine congestions and displacements before mar- 
riage. 

Evidence seems to indicate that marriage between rela- 
tives is reprehensible and that the danger increases with 
the nearness of the relationship, since the children of such 
marriages are prone to disease and to defects in the sense- 
organs, especially the eye and ear, or in mental qualities. 
But upon closer investigation it is probably more nearly 
true that " the objection to consanguineous marriages lies 



260 A MANUAL OF HYGIENE AND SANITATION. 

not in the bare fact of the relationship (of the parties con- 
cerned), bat in the fear of their having similar vitiations 
of constitution." Few families or persons are absolutely 
healthy or free from taint, and " it may safely be as- 
serted that when both parents are possessed of a physio- 
logic or pathologic congenital characteristic, that character- 
istic is almost certain to be repeated in an aggravated form 
in the offspring." 1 We can, accordingly, easily under- 
stand that " in consanguineous marriages the real danger is 
in the strong probability that both parents have some dis- 
tinct taint of degeneration, which is liable to be increased 
in their children, but which might possibly disappear if eaeh 
married a person not bearing the same or some closely 
allied character. The marriage of two individuals of the 
phthisical type, whose families were strangers to eaeh 
other, would he as productive of evil as the marriage of 
first cousins who were phthisically inclined." 2 However, 
any advice on the subject must depend upon the special 
circumstances in each case, but chiefly on the health and 
degree of relationship between the parties. 

Exercise. 

Exercise is generally considered to mean simply the 
action of the voluntary muscles, but it has a wider mean- 
ing than this. Every organ in the body is capable of 
being exercised in some way or other ; and if not prop- 
erly exercised an abnormal state is almost certain to en- 
sue. " Life is organization in action." Each organ has 
its own special stimulus, and if this be normal in amount 
and character, we should have health. Also, the trained 
use of an organ makes it more effective in the performance 

1 Lawrence Irwell : Philadelphia Medical Journal, July 21, 1900. 

2 Ibid., July 28, 1900. 




PERSONAL HYGIENE. 261 

of its functions. But deficiency in exercise favors a lack 
of nutrition, wasting in size and eventually degeneration 
of tissue ; while, on the other hand, too much work may 
favor hypertrophy and tissue degeneration. 

Proper muscular exercise is highly beneficial to health, 
and in the end actually necessary to the proper performance 
of functions in other organs ; it is consistent with and 
necessary to health. But, to be of value, the exercise 
must not only be regular but must consist of movements of 
sufficient force to necessitate energetic contraction of the 
muscles ; we must do work. This necessitates resistance 
as an element, and we may define physical exercise as 
voluntary labor. We need the resistance to obtain the 
proper contraction of the muscles, the contraction for 
their disintegration, the disintegration for their renewal, 
etc. ; for we know that upon the constant destruction 
and disintegration of tissues depend their subsequent 
renovation, and that the strength and vigor of all parts of 
the body and of the whole depend upon its newness. 

Beside the fact that proper physical exercise makes the 
voluntary muscles larger, harder, stronger and more 
quickly responsive to the will, and that it increases the 
functional capacity of the involuntary muscles employed, 
it largely promotes health and strength by quickening the 
circulation and increasing the respiratory powers. Dur- 
ing muscular action (contraction) there is a conversion of 
potential energy into motion, a call for more food, an in- 
creased demand for and consumption of oxygen, and an 
increased production of and elimination of carbonic acid 
and other waste matters. 

This increased demand for oxygen and elimination of 
carbon dioxide necessitates increased action of the respira- 
tory organs — the lungs, and this is one of the greatest 



I 



262 A MANUAL OF HYGIENE AND SANITATION. 



advantages of physical exercise. The respirations are in- 
creased in frequency and depth, the lungs expanded, the 
air vessels flushed out and refilled with each inspiration. 
Doubtless many cases of pulmonary tuberculosis could be 
prevented or cured if only people could be taught to take 
proper exercise and to breathe properly, for we rarely 
find the lungs fully expanded except in the out-door worker 
or athlete. Consequently, the movements of any given 
exercise should be with speed and force sufficient to 
quicken and deepen the respiration ; and, conversely, if 
any severe exercise is to be undertaken or a course of 
training begun, special care must be had to develop the 
lung capacity. 

A man walking at the rate of four miles per hour in- 
spires five times as much air as when reclining at rest, 
which latter amount is, for an adult, about 480 cubic 
inches per minute. Or, as Pettenkofer has shown, a man 
on a day of rest absorbs 25 ounces of oxygen and throws 
off 32 ounces of carbon dioxide and 29 ounces of water; on 
a day of work he absorbs 33.6 ounces of oxygen and 
throws off 45 ounces of carbon dioxide and 72 ounces of 
water. In other words, the elimination of pure carbon 
on a work-day is more than three-fourths of a pound. 

Muscular exercise is necessary, therefore, for the proper 
elimination of waste carbon from the body, and, as the 
action of the muscles is checked and lessened if the carbon 
dioxide produced by their action is not immediately car- 
ried off by the blood and eliminated by the lungs, it 
follows that during exercise there should be nothing to 
impede the circulation or the action of the chest and 
lungs, and that all tightness of clothing, especially about 
the waist, neck and chest, should be avoided. Moreover, 
inasmuch as the amount of carbon dioxide and other 



PERSONAL HYGIENE. 263 

waste matters eliminated is so very much increased during 
exercise, a much larger amount of pure air is needed, and 
all rooms and buildings wherein exercise is to be taken 
should be well ventilated. 

After exercise an increased amount of carbonaceous 
food and of water must be supplied to replenish the sys- 
tem for what has been eliminated. The increase of carbon 
food is probably best given in the form of fat rather than 
of the carbohydrates, though there is some difference of 
opinion on this point ; and of all fluids, water is doubt- 
less the best in ordinary cases for training. As a general 
rule, alcohol is harmful, because it benumbs and deadens 
the nerves and will, and because, as every voluntary impulse 
must originate in the brain, anything that interferes with 
the communication between it and the muscles must lessen 
the promptness with which they respond and the conse- 
quent efficacy of their work. The use of a small quan- 
tity of malt liquor, however, as a tonic or after the exercise 
is finished may not be harmful, but the decision as to its 
need or use should be left to the physician or trainer 
rather than to the one taking the exercise. 

By exercise the action of the heart is increased in force 
and frequency, the pulse is made full and strong if the 
work be not too excessive or sudden, and the flow of blood 
and other fluids is increased throughout the whole body. 
As long as the heart is not overtaxed the pulse beats are 
regular and even, though suddenly increased exertion 
may make the rate very rapid. Ordinarily exercise in- 
creases the rate from ten to thirty beats per minute. Ex- 
cessive exercise leads to palpitation and hypertrophy of the 
heart (one reason why any extensive training should be 
under a competent trainer) ; but, on the other hand, 
deficient exercise leads to a weakening of the heart muscle 



264 A MANUAL OF HYGIENE AND SANITATION. 

and heart action, and probably to dilatation and fatty 
degeneration. If at the beginning of a new exercise 
the heart action becomes irregular, rest should be taken, 
and the exercise then begun in a more moderate and 
gradual way. The heart stimulus is largely due to the 
increased amount of blood in its cavities, but it should be 
remembered that the venous circulation is chiefly due to 
the muscles. " Every muscle is a little heart, ?; and these, 
by their contraction, constantly tend to drive the blood 
onward to the true heart and lungs. 

Exercise greatly increases the amount of perspiration 
from the skin, this perspiration containing water, salt 
and considerable waste matter. The evaporation of the 
water tends to keep the body cool, but on account of the 
great heat production there is not much danger of chilling 
the body during exercise. As soon as work is stopped 
heat production is checked, the body cools off rapidly, 
and then there is danger of chilling unless more clothing 
be added. Flannel is best for this, because it is a non- 
conductor of heat and hygroscopic and so prevents too 
rapid cooling of the body. Keep the skin clean so that 
the sweat-glands may be unobstructed in the performance 
of their functions. 

Exercise increases the appetite, partly because of the 
increased demand of the muscles for food and partly on 
account of the increased circulation of the blood through 
the vessels of the alimentary tract and the liver, this 
causing a more perfect digestion of food. 

If exercise be taken too soon before meals either the 
stomach, by calling the blood from the exhausted muscles, 
will prevent their proper repair and rest ; or the muscles, 
calling the blood from the stomach, will prevent the 
proper formation of the gastric juice when food is intro- 



PERSONAL HYGIENE. 265 

duced. If exercise be taken too soon after eating, it is 
apt to prevent the flow of blood to the organs of digestion 
and the formation of the digestive juices ; or, by forcing the 
contents of the stomach into the intestines before gastric 
digestion is completed and before the food has reached a 
condition in which the intestines can make use of it, to 
cause intestinal irritation and indigestion. 

Proper physical exercise favors a symmetrical brain 
development, for it not only sends more blood containing 
food and oxygen to this organ, but exercise of the func- 
tions of the centres governing the action of the muscles 
must favor the growth and development of those centres. 
" Hand culture, apart from its value per se, is a means 
toward more perfect brain culture/' and exercise by itself 
alone is truly educational, although this feature of it may 
be more fully developed and emphasized by proper systems 
and methods. The great trouble is that it is extremely 
liable to be misapplied, misunderstood or neglected. 

The aim of training should be to increase the capacity 
of the lungs and the breathing power, to strengthen the 
heart and the circulation, to invigorate the brain and 
nerve-centres, to improve digestion and nutrition, to 
make the muscles more powerful, more responsive to the 
will and their capacity for endurance greater, and to 
lessen the amount of adipose tissue. Systematic exercise 
also helps one to resist disease, because by it waste mat- 
ters are carried off ; pores, glands and organs are kept at 
work and healthy, and active tissues take the place of 
weak and sluggish ones. 

Fatigue is due to lack of contractile material in the 
muscles to continue work, to the exhaustion of nerve- force 
and motor impulses from the brain, and to accumulation 
of waste products in the muscle. 



266 A MANUAL OF HYGIENE AND SANITATION. 

Active exercise is that brought about by one's own 
movements ; passive, that produced by something out- 
side or collateral to one's own power. 

It is hard to determine how much exercise any given 
person ought to take, as the personal equation varies so 
much. The average healthy man should probably do 
work equivalent to 150 foot-tons daily. The work of 
walking on a level at the rate of three miles per hour is 
said to be equal to that of raising one-twentieth of the 
body-weight through the distance walked. According to 
this, a man of 150 pounds in walking one mile does work 
equal to 17.67 foot-tons, and his total daily physical labor 
should be equivalent to walking about nine miles at the 
above rate to get the proper amount of daily exercise. 
This seems like an excessive amount, but if the actual 
physical work of one's customary vocation be taken 
from this, it will not leave so very much for the daily 
health-task ; and while the natural disinclination of many 
to exercise grows stronger by indulgence, and while 
urgent reminders are wanting and the evils arising from 
the neglect, abuse or misuse of exercise are not so very 
immediate or apparent, the latter are still certain to result 
and are not at all consistent with good and perfect health. 

Bathing. 

In health we make use of baths and bathing for the 
cleansing of the body, the stimulation of the functions of 
the skin, and as a tonic to the whole system. A proper 
bath properly taken is exhilarating and thoroughly enjoy- 
able. Baths are also to be employed in sickness as a 
means of cure, but such use of them is foreign to the 
present discussion. 



PERSONAL HYGIENE. 267 

Dr. H. C. Wood says : " Cleanliness and the main- 
tenance of the proper condition of the skin require the 
use of the bath at least twice a week. In some very 
delicate persons the general bath produces marked depres- 
sion, but this can almost always be avoided by the use of 
very hot water. If the hot or warm bath be employed 
habitually, it should be preferably taken at night, and, 
unless under very exceptional circumstances, the hot bath 
should always be followed by cold sponging or the cold 
shower-bath, or by a plunge into cold water. " The tem- 
perature of a cold bath may be from 40° to 75° F. ; a tepid 
bath, 75° to 85° F.; a warm one, 85° to 100° F. ; a hot 
one, from 100° to 110° F. A cold bath is taken not so 
much for its cleansing as for its tonic and stimulating 
effects ; the others are used mainly for their cleansing 
properties, though if followed by the cold sponge, shower 
or dip, the sense of exhilaration produced will be marked. 

Cold baths taken immediately after physical exercise 
while the body is still warm, but after perspiration has 
ceased, and followed by a good rubbing and friction of the 
skin, dispel fatigue and give a sense of buoyancy and 
lightness. The shock of the first contact of the water 
with the skin is but momentary, and can be withstood 
by most persons, unless there be serious organic disease ; 
and the reaction produced certainly compensates for the 
primary discomfort. If the bath be taken in the open air, 
there is the additional benefit of a plentiful supply of 
fresh air for the lungs, of the physical exercise and the in- 
creased circulation induced by swimming or combating 
the surf, and, if in the sea, of the stimulation of the skin 
by the salt water. In fact, sea-bathing may be advan- 
tageous to a marked degree where the circulation and 
action of the skin are sluggish. 



268 A MANUAL OF HYGIENE AND SANITATION. 

Those who are subject to organic heart disease should 
not indulge in sea-bathing nor in deep fresh-water bath- 
ing where a sudden tax may be made upon the strength 
and the heart action be disturbed or checked. Women 
who are menstruating or who are in the later months of 
pregnancy should not take cold baths. 

Baths should not be taken too soon after meals, because 
digestion may be lessened or entirely stopped by the blood 
being called from the stomach to the skin and muscles, 
and nausea and vomiting thus induced. " There can be 
no doubt that many of the cases that are called ( cramps/ 
and which frequently result in drowning, are due to this 
cause." 1 In cold baths the head should be immersed 
first, u to avoid increasing the blood-pressure in the brain 
too greatly, which might result if the body were gradually 
immersed from the feet upward." 2 

The following rules/ issued by the English Royal 
Humane Society, are worth noting: u Avoid bathing 
within two hours after a meal, or when exhausted by 
fatigue, or when the body is cooling after perspiration. 
Avoid bathing altogether in the open air, if, after having 
been a short time in the water, there is a sense of chilli- 
ness, with numbness of the hands and feet ; but bathe 
when the body is warm, provided no time is lost in get- 
ting into the water. Avoid chilling the body by sitting 
or standing undressed on the banks or in boats after hav- 
ing been in the water. Avoid remaining too long in the 
water, but leave the water immediately if there is the 
slightest feeling of chilliness. The vigorous and strong 
may bathe early in the morning on an empty stomach ; 
the young and those who are weak had better bathe two 

1 Robe's Text-book on Hygiene. - Ibid. 



PERSONAL HYGIENE. 269 

or three hours after breakfast. Those who are subject to 
giddiness or fainting, or suffer from palpitation or other 
sense of discomfort of the heart, should not bathe (out-of- 
doors) without first consulting their physician. m 

After any kind of a bath the body should be thor- 
oughly dried, not only to restore and accelerate the circu- 
lation of the skin by the friction and to prevent the 
cooling by the evaporation of the water, but also to pre- 
vent chafing and eczematous eruptions where the skin is 
subject to the friction of clothing. Warm or hot baths 
should not be taken if the person is to be exposed to the cold 
within several hours, and the same rule applies to Turk- 
ish, Russian or vapor baths ; so the former had best be 
taken in the evening, and the latter should not be taken 
away from home, especially in cold weather, unless the 
bather takes pains to rest for a time after the bath, and 
then to wrap up well before going into the open air. 

In all warm baths in health the principal object is to 
secure the cleansing effects, and to be effective their use 
must be systematic. The pores of the skin are self- 
cleansing only to a certain degree, and the free use of 
warm water is most beneficial in removing dry epithelium, 
sweat, dirt and grease. If the pores of the skin are ob- 
structed, there are not only irritation and eruptions of the 
skin produced, but more work is thrown upon the kid- 
neys, and these, if unsound, will break down the quicker. 
Soft water is to be preferred for ordinary bathing and 
washing, because it often prevents or reduces cutaneous 
irritation, and because it saves soap. 

A Turkish bath consists : 1. Of a dry, hot-air bath 
at a temperature of from 120° to 170° F., or even higher, 

1 See also Sea Air and Sea Bathing, by Dr. John H. Packard. 



270 ^ MANUAL OF HYGIENE AND SANITATION. 

for from ten to thirty minutes. This causes in most persons 
extreme perspiration with no sense of discomfort, but 
rather a very pleasant sensation. After this come : 2. 
A hot shower bath to wash off the sweat. 3. Shampoo- 
ing, massage and scrubbing to thoroughly remove all 
dirt, loose epithelium and perspiration from the skin. 
This is in moist air at from 100° to 110° F. 4. A warm 
shower bath gradually changing to a cold one, and then 
a thorough drying of the body and a rest for a quarter or 
half an hour. A Russian bath differs from this only in 
that moist air at 150° F. or less is used instead of dry 
air for the first bath. 

It has been said " that a person ought never to stay in 
either the hot air or steam-room if in any wise oppressed, 
or to use very cold water afterward if one feels any 
shrinking from it." Nor should one who is very corpu- 
lent or subject to organic heart disease take a Turkish or 
Russian bath without the advice of a physician. But for 
healthy persons they are very pleasant and in most cases 
beneficial, provided they are not taken too often and that 
one does not indulge in them too long at a time. 

The terms sun-baths, mud-baths, sand-baths and pine- 
needle baths are self-explanatory. These are used in 
treating certain diseases and are supposed to do some 
good, especially in rheumatic affections. 

Clothing. 

There is scarcely anything that can be said on this sub- 
ject with which almost every one of ordinary intelligence 
is not in some respects conversant. According to Dr. 
Poore, the main objects to be sought in clothing the body 
are : " 1. To maintain the temperature and, by preventing 



PERSONAL HYGIENE. 271 

the loss of animal heat, to diminish to some extent the 
demands for food. 2. To allow the chief heat-regu- 
lating mechanism — i. e., the evaporation from the skin — 
to proceed with as little hindrance as possible. 3. To 
allow all muscular acts the greatest possible freedom, and 
to avoid the compression of the body in so far as may be 
possible. 4. To protect the body from heat, cold, wind 
and rain. 5. To disguise as little as may be the natural 
beauties of the human figure/' 1 

The substances from which articles of clothing are usu- 
ally manufactured are wool, silk, cotton, linen, leather 
and furs, although almost everything that can possibly 
be fashioned to suit the needs or fancies of the wearer is 
or has been utilized for the purpose. Goods of all manner 
and kind are woven from the first four substances men- 
tioned, either singly or in combination one with another, 
and felts are made from wool, hair or fur, these latter 
being made, not by weaving, but by an interlacing and 
matting together of the fibres by pressure and rubbing. 

In a general sense wool is probably the most valuable 
of clothing materials, since in a variable climate or 
where there are sudden changes of temperature, it is the 
safest for the wearer to use. While, taking fibre for 
fibre, it probably does not vary so much from linen or 
cotton as a heat conductor as is generally believed, it is 
usually woven in such a way as to entangle large quan- 
tities of air in its meshes, thus preventing either sudden 
lowering or raising of the body-temperature, since dry 
air acts as an especially good non-conductor of heat. 
Moreover, wool is extremely hygroscopic, taking up 
water and perspiration very readily and giving them off 

1 Stevenson and Murphy : Treatise on Hygiene. 



272 A MANUAL OF HYGIENE AND SANITATION. 

slowly, thus reducing the cooling by evaporation to a 
minimum and regulating the heat-dissipation of the body. 
All who are at all subject to rheumatism or to such symp- 
toms as are dependent on sudden temperature changes 
should wear woollen garments next to the skin the year 
round, varying the thickness and weight, of course, to 
suit the season, and children and others subject to diges- 
tive disturbances will usually be greatly benefited by the 
constant use of a woollen (or, in case that is too heavy, 
a silken) band about the abdomen. 

As it is ordinarily woven, some persons cannot tolerate 
wool next to the skin on account of its irritating prop- 
erties. These latter are obviated, however, if the under- 
garments be made of pure wool woven by methods similar 
to that introduced by Dr. Jaeger, or of a mixture of 
wool or cotton, or by wearing a net garment of linen or 
cotton next the skin and underneath the woollen under- 
clothing. The Jaeger method, by the way, is said to pro- 
vide for the escape of moisture from the material and for 
the air permeating freely through its interstices. 

Silk is a good non-conductor of heat, and is almost as 
hygroscopic as wool, so that it is good material from 
which to make warm clothing. Its great natural beauty 
and the facility with which it takes coloring matter also 
make it desirable from an aesthetic stand-point, but its 
great disadvantage is its high cost. For those who can- 
not wear wool next the skin and to whom the cost is no 
objection, silk is an excellent material for undergarments. 

Cotton is probably the most generally used for clothing 
of all the fibres. It is not as hygroscopic by far as wool, 
but it is hard and durable, and is, above all, cheap, so that 
it furnishes the bulk of the clothing for the masses. If 
smoothly woven and of a light color, it makes extremely 



PERSONAL HYGIENE. 273 

cool garments for warm climates or seasons. On the 
other hand, if warm clothes are desired, the cotton must 
be woven so as to have large air spaces in the fabric, thus 
making it resemble the ordinary woollen clothing in text- 
ure and partly in function. Cotton should not be worn 
next the skin by those subject to sudden temperature 
changes, nor during exercise, unless it is changed in the 
latter case immediately after the exercise or some addi- 
tional clothing is added to the body to prevent too rapid 
evaporation and cooling. 

Linen is valued for its purity of color when bleached, 
and for its durability. It is more expensive than cotton, 
but its hygroscopic and heat-conducting properties are 
about the same as the latter. It is especially desirable 
for making clothing for hot climates and for articles of 
dress that are easily soiled and need frequent cleansing. 

Furs provide extreme protection against the wind and 
cold, both on account of the impermeability of the skin 
and of the large quantity of air entangled in the fur itself. 

Leather is utilized for foot-coverings, etc., on account of 
its durability, pliability and practical imperviousness to 
moisture, especially when oiled ; and in cold countries is 
also used for body garments, on account of its resistance 
to the wind and the efficacy with which it keeps the body 
surrounded with a layer of warm air. 

With the possible exception of rubber, which is espe- 
cially useful for the protection which it gives from wet 
and wind and rain, other materials from which clothing 
is made need not be mentioned here, because of the com- 
parative rarity of their use and their close resemblance to 
those already mentioned. The value of any material for 
clothing purposes, however, may be said to depend upon 
the slowness with which it permits the passage of heat to 

18 



274 A MANUAL OF HYGIENE AND SANITATION. 

or from the body and the evaporation of water, the 
amount of air its meshes contain, its impermeability to 
the wind, or else its special adaptability to some special 
purpose. 

Certain materials are manufactured from combinations 
or mixtures of two or more of the four fibres first men- 
tioned, and it sometimes becomes necessary to distinguish 
these one from another and to determine the proportion 
of each in the goods. This is done by microscopical ex- 
amination, each fibre having its own peculiar character- 
istics, and by chemical reactions. Some of these latter 
are as follows : Wool and silk dissolve in hot liquor 
potassse or sodge of a specific gravity of 1050, while cotton 
and linen are not affected. Wool and silk are stained 
yellow by strong nitric or picric acid ; cotton and linen 
are not. Sulphuric acid affects wool but little, slowly 
dissolves silk, and changes cotton or linen into a gelatin- 
ous substance that is colored blue by iodine. Hot con- 
centrated zinc chloride dissolves silk, but not wool ; and 
copper dissolved in ammonia rapidly dissolves silk and 
cotton, linen more slowly, but only swells the wool a little. 

Cloths are often fraudulently sophisticated in the pro- 
cess of manufacture, and their value greatly lessened 
thereby. Wool is mixed with u shoddy/' which is made 
from old and used woollen rags torn asunder and then 
respun with an addition of fresh wool ; silk is heavily 
weighted with salts of tin, iron or with other substances, 
and cotton and linen are stiffened and glossed with an 
excessive amount of starch, white earth or the like. 
Shoddy can be determined by the use of the microscope ; 
the weighting of silk by chemical reactions and solutions ; 
and overstarching, etc,, of cotton and linen by washing 
and drying. 



PERSONAL HYGIENE. 275 

It will not be advisable here to go fully into the con- 
sideration of the influence which the shape and style of 
the individual garments of ordinary use have upon health, 
for that would require a much longer discussion than the 
present space would allow ; but the general rule may be 
laid down that each article of clothing should be adapted 
to the peculiar ueeds and occupation of the wearer, and 
that it should in nowise interfere with the proper develop- 
ment, use or physiological functions of any part of the body. 

Trite and hackneyed as is the subject, the writer feels 
that he would be wanting in the performance of his duty 
if he failed to condemn the habits and fashions of dress 
that demand the undue constriction of the trunk of the 
body. All sanitarians practically agree upon the impor- 
tance of " vital capacity," as measured by the develop- 
ment and extent of expansion of the thorax, in determin- 
ing the constitution and health of the individual. But 
not only does the corset do harm by interfering with the 
functions of respiration and circulation, but it also de- 
forms and induces even more serious troubles by its dis- 
placement of the abdominal and especially of the pelvic 
organs, and by the grave interference with the nutrition, 
tone and function of all of these. It is a fair challenge 
to any woman who declares that she does not dress too 
tightly, to ask her to honestly measure her waist circum- 
ference and expansion both with and without the garment 
in question, and to make her decision accordingly. And 
it is certainly false doctrine to teach, as is so often done 
to young girls, that it is really necessary that the normal 
human body should have artificial support. The natural 
muscles kept in proper training, tone and action are all 
sufficient to give the most perfect and most beautiful 
human form. 



276 A MANUAL OF HYGIENE AND SANITATION. 

When exposed to the sun's rays or to other sources of 
radiant and incandescent heat, fabrics absorb heat, irre- 
spective of the constituent materials, but in the following 
order as regards color : White, light yellow, dark yellow, 
light green, Turkey red, dark green, light blue and 
black, the latter color absorbing more than, and light 
blue almost twice as much as white, the material in each 
case being the same. In the shade the absorption depends 
more on the material than on the color. 

Lastly, it should be remembered that, as disease germs 
are readily conveyed from place to place and from one 
person to another by the clothing, and especially by that 
which is hygroscopic by nature, care should be taken to 
keep the garments in as cleanly and aseptic condition as 
possible, to disinfect them whenever they have been ex- 
posed to infection, and, for those who are much among 
the sick or liable to infection, the use of smooth, closely 
woven, non-hygroscopic over or outer garments that can 
be readily cleansed, such, as cotton or linen, is to be 
highly recommended. 

Light. 

The important influence of sunlight in the development 
and maintenance of a healthful condition in all higher 
organisms, both animal and vegetable, is well known by 
every one, but as yet there is a lack of information as to 
the exact physiological methods and processes which are 
due to this great force. We know that, for the plants, 
chlorophyll is the intermediary agent which largely assists 
in the conversion of carbonic acid and the storage of car- 
bon in various compounds, and that the presence and 
action of this chlorophyll are largely dependent upon the 
light-supply ; while for the animal kingdom, and espe- 



PERSONAL HYGIENE. 277 

cially for the human race, it is evident that the effect 
of sunlight is manifested more or less directly in the 
blood and skin, though the whole body quickly manifests 
a marked appreciation of its presence or absence. But 
when this has been said, there is little else that can be 
added as a matter of positive information. No one knows 
just how the pallid and anaemic child that has been reared 
in the shade and dark is converted into the tanned and 
ruddy picture of health in so short a time, but the results 
are unquestionable. 

The subject demands much further study, and it may 
not be out of place to indicate one or two directions in 
which the investigation may, perchance, be wisely pur- 
sued. 

In the first place, there has doubtless been too little 
appreciation of the fact that the sunlight in its totality 
has many other rays of force than those which manifest 
themselves alone to our sense of sight. The existence of 
the ultra-violet rays and the fact that these are more 
powerful actinically than those of the ordinary spectrum 
have been satisfactorily demonstrated, and the only ques- 
tion is as to what the true power and influence of these 
invisible rays may be. It is not certain as yet that some 
of them, at least, are not closely related to the new mani- 
festation of force discovered so recently by Rontgen, and 
there is good reason to believe that the penetrative powers 
of light as regards the human body are not yet fully known 
or appreciated. 1 Nor can we tell how much of that power 

1 Some experiments by the author and by numerous others seem clearly to in- 
dicate that some of the radiant energy from the sun, and in lesser degree from 
other sources of light, is able to penetrate substances hitherto considered opaque, 
and to produce phenomena similar to those due to the Rontgen ray. Conse- 
quently, if the experiments referred to are well founded, the penetrative ability 
of this energy, as regards the human tissues, would seem to be more than prob- 
able. 









278 ^ MANUAL OF HYGIENE AND SANITATION. 

of the sun whose effects we feel and see is in nature on 
that borderland between light and electricity that is as 
yet so vague and unknown. 

Again, the destructive effect of sunlight, and of light 
from minor sources as well, upon the germs of disease and 
other low forms of life, is now a matter of common 
knowledge, though many are not aware that it has been 
proven that this germicidal action of light is directly in 
relation to its actinic power. Considering this, together 
with the statements of the preceding paragraph, may we 
not surmise that hostile organisms, even in the deeper 
tissues, are overcome both in this way and by the improved 
condition of the blood due to the light, and that this helps 
to explain the good results that follow the open-air treat- 
ment of many diseases and abnormal conditions? The 
tubercle bacilli are especially susceptible to its influence, 
and every one knows that an abundance of sunlight is 
just as essential to the tuberculous patient as is plenty of 
good food, pure air or proper clothing. 

Bie 1 has described a treatment by means of light, and 
has reported some interesting results and apparent cures, 
in cases of lupus of the skin and circumscribed baldness 
(alopecia areata). He states that the power of the 
chemic rays to kill bacteria, to produce an erythema 
or inflammation of the skin and to penetrate the skin 
is already proved. But the strongest light of summer, 
unconcentrated, is too weak to produce marked results 
quickly in disease, and as the chemic and bactericidal 
power of light is mainly in the blue, violet and ultra- 
violet rays, measures are taken to concentrate and in- 
tensify these by means of plano-convex lens filled with 

1 British Medical Journal, September 30, 1899. Philadelphia Medical Journal, 
October 7, 1899. 



PERSONAL HYGIENE. 



279 



a bright-blue solution of copper-ammonium sulphate. 
This also cools the rays, which would otherwise be intol- 
erable, and further cooling is secured by a smaller hollow 
plano-convex lens of quartz, through which water is made 
to flow and which is applied to the part of the skin under 
treatment and on which the concentrated rays impinge. 
That the treatment promises much for the future seems 
uudoubted. 

More might also be said in reference to the possible 
and probable chemic activity of the light in and upon the 



Fig. 43. 




Lighting by prismatic devices. (Pyle.) 

metabolic processes of the animal body ; but as there is 
still the uncertainty of hypothesis and theory, it may be 
wiser to simply leave the foregoing suggestions as food 
for thought and incentives to further research and inves- 
tigation. 

The importance of an abundance of daylight in all 
rooms where much work is to be done should not be over- 
looked. Not only is it necessary for the sake of the 
influences just mentioned, and as a destroyer of patho- 
genic organisms, but it is more agreeable and safer for 
the eyesight than almost any form of artificial light yet 



280 A MANUAL OF HYGIENE AND SANITATION. 

] 

devised. An important aid to the illumination of dark 
interiors has been the recent invention and introduction 
of panes or plates of glass with a series of ridges or 
prisms, which refract and diffuse throughout a room the 
light which would otherwise illuminate it but partially or 
not at all. The prisms are made with various angles and 
may be placed either in the ordinary window sash or in 
projecting canopies, according to whether the direct light 
from the sky is obstructed or not. (Fig. 43.) 

The relation of artificial lighting to ventilation has 
already been discussed. In addition to this point, the 
quantity of light supplied and its steadiness have an im- 
portant bearing on the hygienic value of any artificial 
source of illumination that it may be necessary to select 
and employ. 



CHAPTEK IX. 



SCHOOL HYGIENE. 



It has already been remarked in the chapter on Per- 
sonal Hygiene that the best time for applying and observ- 
ing the laws of hygiene is in the days of childhood and 
youth, for then the whole organism is plastic and yields 
readily to both external and internal impressions and 
forces. 

This being so, the great influence of the factors common 
to school life may be readily conceived, and inasmuch as 
the average child will be subject to them for a large part 
of from eight to ten or more years, the importance of a 
study of school hygiene will not be denied. It concerns 
the parent, the physician and the citizen, and its inves- 
tigations must consider the personal hygiene of the scholar, 
the conditions of his health, his habits, the amount of 
work done, the sanitary environment and requirements 
of the school-room or building, the furniture, the ventila- 
tion and heating, and the influence of all these upon the 
individual's state and development. 

Next to the scholar himself and his parents, these mat- 
ters are of special interest to the physician, for, beside 
being one, who from his special training and education is 
often called to act upon school committees and boards of 
education, he has to treat many disturbances of health in 
the young which have their origin or cause in the harm- 
ful or insanitary conditions of school life. 



282 ^ MANUAL OF HYGIENE AND SANITATION. 

There are disorders to which all children are subject, 
whether in school or out ; but a special class are markedly 
influenced by school life or work, and to these abnormal 
conditions we may give the term u School Pathology. " 
Of some of these overwork is the cause ; others are set 
up by other factors. 

Overwork, coupled with depressed vitality, may give 
rise in children to one or more of the following troubles : 
Dyspepsia, headaches, nervous derangements, chorea, 
epilepsy, neurasthenia, backaches, menstrual disorders 
and, in some cases, consumption. On the other hand, 
bad arrangement of seats and desks, improper location of 
windows, blackboards, etc., may cause spinal and other 
physical deformities, defective eyesight, etc. Of the first 
class, even where the amount of work may not seem or 
may not really be too much for the capacity of the child, 
worry about rank or over an approaching examination 
may have a harmful effect upon a nervous temperament. 
This is especially so if the examinations come at the end 
of a spring term, when the scholars are all more or less 
worn-out and debilitated. The forcing process should be 
avoided as far as possible, and if grades are to be given 
at all, they should be as much as possible for the work 
and attendance during the term, and not so much for the 
actual work done at examination time. 

Moreover, young children should not be kept in school 
for too many hours in the day, nor should the school be 
looked upon by parents as a place to which to send chil- 
dren to keep them out of the way and from mischief. 
Edwin Chadwick has shown that a child from five to 
seven years can only attend to one subject for about fifteen 
minutes ; one from seven to ten, for twenty minutes ; 
from ten to twelve, for twenty-five minutes, etc., and that 



SCHOOL HYGIENE. 283 

the length of individual lessons and likewise the total 
day's work should be arranged accordingly. The very 
early years of school life should be given to inculcating 
correct habits of attention and of morals and to training 
the will and power of concentration, rather than to the 
teaching of any special knowledge. 

But it is probably the work attempted outside after 
school hours, and not the actual work done in the school, 
that is most responsible for the breaking down of health, 
especially in older scholars. In Cleveland, in 1881, of 
186 girls in the high school, 29 per cent, of those who 
studied less than two hours, 70 per cent, of those study- 
ing from two to four hours, 93 per cent, of those study- 
ing from four to six hours, and 100 per cent, of those 
studying over six hours daily out of school, had poorer 
health while at school. Of these same girls, the per- 
centages of those whose health was " very poor while 
at school," dividing them the same way as regards over- 
work, were respectively 14, 40, 6Q, and 100 per cent. 
This loss of health was attributed by the parents to stair- 
climbing, irregularity of meals, worry about rank and 
examinations, etc., but Dr. Goodell says : "So com- 
monly do I find ill health associated with brilliant scholar- 
ship, that one of the first questions I put to a young lady 
seeking my advice is, ' Did you stand high at school V " 
Another writer says : " The effects of anxiety are worse 
than carrying heavy loads." 

In fact, one of the leading educators of the country has 
suggested that children should not be required to study 
reading, writing or drawing before the age of ten or 
eleven, as these bring into action and use the close appli- 
cation of the finer sense organs and faculties which are 
not as yet fully developed ; but he advises that the 



284 A MANUAL OF HYGIENE AND SANITATION. 

instruction of the earlier years of school life should consist 
mainly of language lessons, history, nature studies and 
such others as may be taught orally and that will at the 
same time develop the child's powers of attention, obser- 
vation and reasoning. There is more than a chance that 
such a plan of instruction would not only secure better 
results from the teacher's point of view, but that it would 
also be safer for the scholar's physical organism. 

While a child is at school its mind should not be 
wearied by outside tasks, as music or painting lessons, 
nor the body weakened by social dissipations, late hours 
and indigestible food. Girls are more susceptible to dis- 
turbances, and are more subject to them because they are 
more willing to undertake extra or double work than boys 
and because they are more ambitious and worry more 
about rank. In all children the obtaining of good health 
and a sound constitution is of the first importance. 
Youth is the time for gaining health, not for losing it ; 
for building up sound bodies and constitutions, not for 
breaking them down, and school life should always have 
the former as one of its greatest ends. Of what use is all 
the learning one may gain before the age of eighteen, if there 
be no strength to use it afterward in the battle of life ? 

School life is sometimes responsible for dyspepsia by 
interfering with the regularity of meals, the children 
missing the midday meal and having to depend upon a 
meagre lunch, often of sweets and indigestible food. This 
is especially important when the rest of the family dine 
at noon and there is only a light meal served in the even- 
ing. Again, many habitually lose their breakfast through 
fear of being late, or else bolt the food without masticat- 
ing it and gulp down hot coffee or tea before starting on 
a run for school. But often the loss of appetite is due 



SCHOOL HYGIENE. 285 

simply to lack of fresh air and proper exercise, or else 
to the nervous condition of the child, which is sometimes 
such as to interfere with almost all of the body functions. 
Such dyspepsias are to be treated by attention to the 
foregoing points rather than by medicine. 

Headache is a common disturbance among school chil- 
dren, and may be due to any one of several causes, among 
which are overwork — producing irritability and disturb- 
ances of cerebral circulation — indigestion, bad air, eye- 
strain, etc. The eyes should always be examined when 
headaches are persistent, and any defects corrected by 
proper glasses. Associated with the headaches, frequent 
bleeding from the nose may occur and should not be 
overlooked, as it may indicate circulatory disturbance. 

One of the most common symptoms of nervous derange- 
ment is sleeplessness or restless sleep, and this condition 
should give warning that something is wrong. Dr. Fol- 
som says : " I doubt whether there is an exaggerated 
prevalence of manifest or well-marked diseases of the ner- 
vous system among school children. If due to the school- 
drill, my impression is that they come for the most part 
later in life, after the children have left school, and be- 
cause of constitutions weakened during school years, 
instead of strengthened as they should be." Children 
subject to chorea or epilepsy should not attend school, not 
ouly for their own sake but for that of the other children, 
who may be unduly affected by their nervous manifesta- 
tions. They should be educated quietly and cautiously, 
with proper treatment and plenty of out-door life. Neu- 
rasthenia or general break-down may occur, usually from 
overwork, and especially among young women. It may 
come on unexpectedly after the examinations at the end of 
the term, when the strain and excitement are removed. 



286 A MANUAL OF HYGIENE AND SANITATION. 

Menstrual disorders are also apt to occur among girls 
that are being overworked mentally, and we ought to 
remember that at the time this function is developing the 
system is undergoing a heavy strain. Also, for certain 
young women rest from customary work is necessary at 
the time of the periodical recurrence, and excuses for ab- 
sence at this time ought to be freely granted. It has been 



Fig. 44. 




Position assumed in writing with the desk too high. (Pyle.) 

well said that Ci girls get through as much work as boys, 
working in their own way." 

The development of consumption may be due to the 
school life, though it is hard to say how frequently this 
is the case. Bad air and overwork are both important 
factors in its production, and if these are forced on under- 
fed or predisposed children the disease may be provoked. 



SCHOOL HYGIENE. 



287 



u In a consumptive family the steadfast rule should be that 
the mind be wholly subservient to the body's welfare. " 

The main cause of spinal and other deformities and de- 
fective eyesight is apt to be found in faulty construction 
of seats and desks, improper location of windows, etc., 
though excessive work or strain may maintain a low 
vitality and act as a predisposing condition. The latter 



Fig. 45. 




Position assumed in writing with the desk too low. (Pyle.) 

point is shown by the fact that spinal curvatures are more 
prevalent in those especially prone to weakness of the 
muscles, as women and girls. But no desk or seat will 
remove original weakness of muscle as the one important 
predisposing condition, and children cannot be made 
strong by supports. " Spinal curvature is not only a 
product of low vitality, but does harm by permanently 
fixing vitality at a low standard." 



288 A MANUAL OF HYGIENE AND SANITATION. 

Bad seats and desks not only cause spinal deformities, 
but help to cause defective eyesight by making the scholar 
hold the book too near the eyes and by making him bend 
his head so that the circulation of blood is impeded and 
ocular congestion favored. However, no seat can be de- 
vised in which a child will maintain a correct or " normal " 
position for any length of time, as this is an impossibility 
for young children ; but the true aim should be to furnish 
a seat in which one will naturally assume the correct posi- 
tion after having temporarily taken any other. " Move- 
ment is a child's way of resting ; rest is a kind of work, 
to be taught by degrees." Seats should have backs to 
prevent fatigue, but a comfortable back gives support to 
the lower part of the spine rather than to the shoulders 
and upper part of the spine. Many foreign authorities 
advise seats with backs only high enough to support the 
lower part of the spine, and low enough for the scholar 
to rest his elbows upon them while studying. 

The following points, suggested by Dr. Lincoln, are 
worth noting: ".1. The chair is often too high for young 
scholars. The most convenient plan may be to provide 
footstools. 2. The seat from back to front ought to be 
long enough to support the whole thigh. A more or less 
spoon-shaped hollow in the seat is commonly thought de- 
sirable. The curve of many settees is such as to produce 
pain at the point where the tuberosities of the ischium rest 
on the wood ; the support is there not wide enough. 3. 
Seats must have backs. The straight, upright back 
reaching to the shoulders is bad ; a straight back, slightly 
tilted, is not bad. American seats are commonly curved, 
with curved backs. 4. The edge of the desk should come 
up to, or overlap, the edge of the seat. The recognition of 
this fact is a recent discovery. 5. Most of our best desks 



SCHOOL HYGIENE. 289 

are too high relatively to the seat, doubtless to prevent 
the pupil from stooping. Something is gained in con- 
venience of reading by this plan, but it interferes with 
correct positions in writing. The elbows, hanging freely, 
should be only just below the level of the lid.' 7 For 
near-sighted children the higher desk may be a necessity 
in writing ; if the desk is made low a portable writing- 
stand may be placed on top of it when necessary. 

Windows on only one side of a large school-room may 
not give sufficient light for the desks most remote from 
them. Consequently, there should be windows on two 
sides, preferably adjoining ones, of large school-rooms. 
The windows should be at the back and to the left of the 
scholar, thus giving the best light upon the desk for 
either reading or writing. They should not be placed in 
front of the scholars, as the continuous light and glare is 
very trying and injurious to the eyes. They should ex- 
tend almost to the ceiling and have square tops, to admit 
of as much light as possible. Blackboards should have 
a dead-black surface, not a glossy one, and should be on 
the sides of the room on which there are no windows. 
Walls should be of a neutral tint, not glaring white. 

Construction of School-houses. The principles 
already given as to ventilation, heating, water-supply, 
etc., apply here as elsewhere. From 1800 to 2500 cubic 
feet of fresh air should be ^supplied to each scholar per 
hour. In cold weather this should, of course, be satis- 
factorily heated. The air-ducts, both inlets and oatlets, 
must be large enough to change the air without causing 
injurious and uncomfortable draughts ; and these ducts 
should be as short and free from bends as possible, or 
better, the rooms should open into the supply and ex- 
haust shafts directly. The air may be warmed either 

19 



290 A MANUAL OF HYGIENE AND SANITATION. 

by steam or hot- water coils or by a furnace, though pre 
ferably by the former, to avoid " baking " the air, anc 
also preferably by the indirect system. There is no ob 
jection to having additional heating apparatus in the 
school-room, provided it is guarded so that the scholars 
may not be accidentally burned. Any system that will 
give a sufficient supply of fresh air properly heated will 
of necessity be more expensive than the old way of not 
ventilating at all except by opening the windows at recess 
time, but experience shows that the increase in expense 
is not so very great, as so much heat is lost by opening 
the windows in this way, and the benefit to the children 
more than compensates for the additional outlay. Country 
schools may be heated by stoves surrounded by sheet-iron 
drums, and ventilated with fresh air from without brought 
in near the bottom of the stove. Passing up between the 
stove and drum the air is warmed and gives good venti- 
lation without chilling or draught. As great a length as 
possible of stovepipe should be exposed in order to get 
the full benefit of the heat from it. 

The Smead system of ventilation and heating has been 
used with satisfaction in many schools throughout the 
country. In this, the air after being warmed and brought 
into the school-rooms at a level a few feet above the floor, 
circulates through them and is finally withdrawn through 
registers at the floor level, whence it is carried under- 
neath the floors to large outlet shafts in which a draught 
is constantly maintained. In this way a thorough diffu- 
sion and changing of the air in the school-rooms is secured, 
and, moreover, the floors are kept warm by the heat from 
the air which is passing beneath them but which would 
otherwise be lost and wasted. 

Ample cloak-rooms should be provided for every school, 



SCHOOL HYGIENE. 291 

which should be warm and well ventilated, in order to 
secure the rapid drying of the garments in wet weather, 
but these cloak-rooms should not, if it is possible, com- 
municate directly with the school-rooms themselves. 
Provision should also be made for readily disinfecting 
them, and, in fact, the whole school building at intervals 
and whenever necessary. 

In 1897 at Newcastle-upon-Tyne, " the experiment 
was tried of closing each school, where scholars were 
being taken ill, for a few hours only, long enough to 
allow of thorough purification and the sprinkling of the 
floors of class-rooms with disinfectants. This disinfection, 
so far as measles was concerned, was followed by the ex- 
tinction of the disease in question." 1 

The school-house should be on dry and well-drained 
soil, as dampness is not only depressing to all constitu- 
tions, but is an important factor in the causation of phthisis 
and strumous diseases. There should not be too much 
shade about, and as many rooms as possible should have 
sunny exposures. If the sunlight is annoying during the 
session, it may be excluded by inside blinds or shutters, 
but we must not lose sight of its helpful influence in the 
destruction of bacteria and purification of organic matters. 

Where sunlight is scanty or it is difficult to illuminate 
the school-rooms, it may be advantageous to furnish one or 
more of the windows with some form of the diffusing and 
refracting prisms already described (p. 280), thus giving an 
abundance of light where there was formerly a deficiency, 
and materially lessening the eye-strain of the scholars. 

Basements of school-houses should be well lighted, 
water-tight and dry, and should be kept scrupulously 

1 American Year Book of Medicine for 1900, pp. 543-4. 



292 A MANUAL OF HYGIENE AND SANITATION. 

clean, that moisture and noxious gases may not be drawn 
into the rooms above. If properly arranged and cared 
for, they may be used as play-rooms in bad weather when 
it would be unwise to send the scholars out-of-doors. 

The water-supply should be free from all impurities 
and as good as can be had. In the country, if from a 
neighboring farm-house spring or well, it may be con- 
taminated by leakage from cesspools and barnyards. Or 
the school water may be taken from a neighboring spring 
or stream which is receiving contamination from the 
school-house cesspool or other sources. For this reason, 
teachers should be taught the tests for chlorides and 
ammonia and the reason for making them, and should 
make these tests frequently. If cause for suspicion 
arises the use of the water should be stopped at once. 

Water-closets and urinals, where in use, should be kept 
clean by a competent janitor, and the principal or head- 
teacher should see that this is done. In the country, the 
pail or earth-closet system ^should be substituted for the 
usual privy- vault or cesspool, and it should be the duty 
of some one apart from the teacher, regularly appointed 
and paid by the school directors of the district, to see 
that removals are made at proper intervals ; the teacher 
should maintain supervision over the daily condition of 
affairs. If possible, the out-houses should be connected 
with the school-house by covered ways, that the children 
may not be exposed in inclement weather ; but these ways 
should be open or else constantly ventilated by open win- 
dows on either side. Cesspools should be at least fifty 
feet distant, and should drain away from the school-house. 

Though approving the Smead system of warming and 
ventilation for school-rooms, the writer cannot say that 
he approves that modification of it wherein the foul air 



I 

i 



SCHOOL HYGIENE. 293 

from the building is carried over the fecal excreta of the 
inmates before being discharged into the outlet shafts and 
carried to the outer air. Though the method rapidly desic- 
cates the excreta and renders it inoffensive to the senses, 
there is danger of the dissemination of disease germs as well 
as a departure from sanitary principles in the method. 

Ample provision must be made for the rapid escape 
and for the safety of scholars and teachers in case of fire 
or panic. Fire-drills should be regularly practised in 
all schools of two stories or more, and presence of mind 
inculcated, that emergencies may be met with safety. 
The comfort of the child should not be forgotten in the 
construction of the school-house, though preservation of 
health is the main aim. 

School Quarantine. As certain diseases are conta- 
gious, it is necessary that school authorities have the right 
to forbid the attendance of such persons as have been ex- 
posed to infection until all danger of transmitting the 
disease to others is passed. This power is usually, how- 
ever, exerted only in the case of those diseases most dan- 
gerous to life and health, though the stringency of the 
regulations varies at different places. Smallpox, scarlet 
fever, diphtheria, measles, and even whooping-cough 
should always be quarantined, and it would be better to 
keep children who are afflicted with minor diseases of this 
class out of school till all danger of infection is over, as 
it is only by rigid measures like this that we may finally 
be able to wipe those maladies out of existence. Consider- 
able evidence now supports the view that there is a 
marked decrease in the prevalence of both scarlet fever 
and diphtheria during the summer holidays and an in- 
crease due to school attendance. But Niven, of Man- 
chester, England, thinks that " the extreme measure of 



294 A MANUAL OF HYGIENE AND SANITATION. 

closing a school for scarlet fever is rarely called for, and 
is not so likely to be effectual as in the case of measles. " l 

Local boards of health should make and enforce rules 
looking to the prevention of the spread of the graver con- 
tagious diseases and should, when necessary, close schools 
and school-buildings till all danger is past. Dr. Lincoln 
gives the following as a system of general regulations : 
" 1. Persons affected with diphtheria, measles, scarlet 
fever, or smallpox (varioloid) must be excluded from the 
schools until official permission is given by the board 
of health for their readmission. 2. Persons living in a 
family or house where such a case occurs are also excluded 
until similar permission is given. 3. This permission is 
not to be given until sufficient time has elapsed since the 
occurrence of the last case to ensure safety, nor until the 
premises have been disinfected under the direction of the 
board of health. 4. If a child suffering from one of the 
above diseases attends school, the premises of the school 
must be disinfected under the direction of the board of 
health before they are used again. 5. Physicians, teachers, 
school officers and school children knowing of such cases 
of disease should at once report them to the board of 
health. 6. The board should also notify the school 
authorities of all such cases. 7. Notice must be sent to 
the family by the school authorities, acting conjointly 
with the board of health. " 

The following table of the periods of incubation of the 
respective diseases is based on an experience of over 
twenty-eight years at the Rugby School, England, by 
Clement Dukes. 2 



1 See Public Health, February, June and September, 1899 ; also, American Year 
Book of Medicine for 1900, p. 538. 

2 Lancet, April 29, 1899. 



SCHOOL HYGIENE. 



295 



An Analysis of the Periods of Incubation. 





Short- 


Long- 




est 


est 


Name of 


period 


period 


disease. 


of incu- 


of incu- 




bation 


bation 




(days). 


(days). 


Scarlet fever 


1 


9 


Chicken-pox 


13 


19 


Mumps, 


14 


25 


Rose-rash 


12 


22 


Measles 


8 


14 



The largest 

number 

occur on the 

following 

days. 



Second and 
fourth 
Fifteenth 

Nineteenth 

Sixteenth 

Elev nth 



The majority of 

the cases arise 

between the 

following days 



Second and 

fourth 
Fourteenth and 

seventeenth 
Seventeenth and 

twentieth 
Fourteenth and 

seventeenth 
Ninth and 

twelfth. 



Percentage re- 
ferring to pre- 
vious column, 
e.g., 59 per ct. 
occur between 
the 2d and 4th 
days. 



10 out of 17 = 

59 per cent. 
24 out of 36 = 

66 per cent. 
50 out of 69 = 

72.46 per ct. 
31 out of 40 = 

77.50 per ct. 
18 out of 24 = 

75 per cent. 



Children having had one of the above-named diseases 
may return to the school with safety after the following 
periods : ' ' Scarlet fever, six weeks from the date of rash, 
provided desquamation and cough have ceased. Small- 
pox and chicken-pox, when every scab has fallen. 
Whooping-cough, after six weeks from commencement 
of whooping, provided the characteristic spasmodic cough 
and whooping have ceased, or earlier if all cough have 
passed away. Diphtheria, not less than three weeks, if 
convalescence is completed ; there being no longer any 
form of sore throat nor any kind of discharge from the 
throat, nose, eyes, ears, etc., nor any albuminuria." 
Wherever possible, a bacteriological examination of the 
nose and throat secretions of a scholar that has had diph- 
theria should be made from time to time, and his return 
to the school should only be permitted when this exami- 
nation no longer shows the presence of the specific organ- 
ism in the secretions mentioned. Rules and regulations 
like the above, when promulgated, " should have the 
force and authority of law, and should be enforced, if 



296 A MANUAL OF HYGIENE AND SANITATION. 

necessary, by the entire power, including school officers, 
etc., of the State.' ? 

Boarding-schools and similar institutions should have 
an infirmary where contagious diseases may be isolated, 
and those in charge should make that isolation from other 
scholars and inmates as complete as possible. At the 
beginning of a term it may be well to subject any who 
have been exposed to contagion to a delay until the prob- 
able period of incubation for the special disease is 
passed, the period dating from the time of exposure. 
With the above precautions it will rarely be necessary to 
close a school, unless a disease is markedly epidemic and 
malignant. 

It is to be hoped that we shall soon have a means of 
inoculating persons against all contagious diseases, as we 
now do against smallpox. At present, boards of health 
and school boards should insist on the vaccination of all 
school children. In Illinois, from 1880 to 1883, the 
deaths from smallpox among unvaccinated children were 
48 per cent.; among the vaccinated, only 0.9 per cent. 
In Philadelphia all who desire it are vaccinated free of 
charge by the vaccine physicians, and it is compulsory 
for all school children. 

Dr. Lincoln has also suggested that further regulations 
similar to the following should be in force in every school 
district : " Every child entering the public schools must 
show a certificate from some reputable physician, giving 
name, age, residence, approximate date of vaccination, date 
of examination, result of examination, the last two to be of 
the physician's own knowledge. The fact of vaccination 
must be entered on the school record and on lists for pro- 
motion and transfer. The school authorities shall an- 
nually report the number of those not protected to the 



SCHOOL HYGIENE. 297 

State Superintendent of Education. School authorities 
may order the exclusion of non-protected persons, after 
sufficient notice, where they think the measure required 
for the public health. Re-vaccination at the age of fif- 
teen may be required under similar circumstances. Those 
unable to pay should be furnished with free vaccination 
by the school authorities. A physician's certificate of 
protection by a previous attack of smallpox is equivalent 
to a certificate of vaccination." 

Contagious ophthalmia is a disease often prevalent in 
charitable and educational institutions and occasionally 
in primary schools, and requires great care to prevent its 
invasion and spreading, as well as to effect a cure. Those 
afflicted with it should be quarantined until there is no 
further discharge or till the granulations on the inner 
surface of the eyelids have disappeared. Enfeebled health 
and poor and insufficient food favor its development, but 
the chief means of contagion is by the use of the same 
wash-basins and towels by a number of children. 

Other diseases that may be transmitted in much the 
same way are chronic conjunctivitis ("granular lids") 
and those due to fungous and other parasites, as the tineas 
(" ringworm of the scalp or face"), pediculosis, etc., all 
of which may be transmitted by an interchange of hats or 
caps or other garments. 

School children should not be allowed to attend the 
funerals of companions dead of a contagious disease, nor 
should funerals be allowed to take place from school- 
houses under any circumstances, owing to the effect on 
the thoughts and sensibilities of nervous children. 



CHAPTER X. 

DISINFECTION AND QUARANTINE. 

As has already been stated, disinfection is that part of 
prophylaxis which has to do with the destruction or modi- 
fication of the exciting causes of disease, and we may 
accordingly define a disinfectant as " an agent capable of 
destroying the infective power of infectious material. " 
Moreover, as with our present knowledge we are practi- 
cally limited in the use of disinfection to the infectious 
diseases only, a disinfectant must also be a germicide. 
Theoretically, it should also have the power of destroying 
the poisonous properties of the toxins which the disease 
germs produce, and which create the characteristic symp- 
toms of the specific diseases ( ; but whether all good disin- 
fectants have this power is by no means proven, and is 
not altogether essential, since by killing the germs we 
check the further production of the toxins, and disinfec- 
tants are mainly used not so much to cure or stop a dis- 
ease in a patient as to prevent its extension to others. But, 
in a popular sense, the term disinfection is given a wider 
meaning than is above indicated, including also not only 
the use of antiseptics and deodorants, but often the actual 
removal of filth and all matters favorable to the growth 
or spread of disease germs, which is, strictly speaking, a 
matter of sanitation. It is needless to say that the latter 
business may be part of the prescribed duties of a disin- 
fector, but it is not one of the essential functions of a dis- 
infectant. 



J 



DISINFECTION AND QUARANTINE. 299 

It will be well here to make the distinction between 
disinfectants and antiseptics and deodorants, as the terms 
are often wrongly used interchangeably, and there is a 
common belief that whatever is a deodorant or an anti- 
septic is also a disinfectant. An antiseptic is an agent 
that retards or arrests bacterial growth and the consequent 
production of toxins or ptomaines, though it does not 
necessarily kill the micro-organisms themselves ; and 
though some autiseptics are germicidal, others are not 
and, therefore, as a class they cannot be considered or 
used as disinfectants. But, on the other hand, u agents 
which kill bacteria in a certain amount prevent the mul- 
tiplication of the latter in culture fluids, when present in 
quantities considerably less than are required to destroy 
vitality." So, a diluted germicide may act as an anti- 
septic and may be used therefor. For instance, chlorin- 
ated lime, which is a good disinfectant in solutions of 
proper strength, may arrest further bacterial growth or 
action in a mass of sewage or filth and prevent the latter 
acting as a culture-medium for disease germs, even 
though the agent be totally inadequate in quantity to kill 
all the micro-organisms present. In the same way, it 
may act as a deodorant — which, by the way, is an agent 
that simply removes or destroys offensive odors, and is 
not necessarily either a disinfectant or an antiseptic — both 
by checking the further action of saprophytic bacteria 
and the consequent formation of putrefactive odors, and 
by actually decomposing and oxidizing those of the latter 
already formed. 

In practical disinfection it is also well to remember 
that while masses of dead organic matter may not in some 
cases contain disease germs and may be even hostile to 
them, in general the reverse of this is more likely to be 



300 A MANUAL OF HYGIENE AND SANITATION. 

true, and decaying matter often furnishes a good field for 
the increase of pathogenic organisms. Moreover, the 
noxious gases given off to the air and the poisonous 
products added to the drinking-water from such masses 
may also do much harm by depressing the system, lower- 
ing the vitality and acting as predisposing conditions to 
the incurrence of such filth diseases as cholera, yellow 
fever, typhoid and typhus fever, diphtheria, etc.; and 
when time or opportunity do not permit of the removal 
of such dangerous accumulations, their power for harm 
should be checked permanently or, at least, temporarily 
by the use of suitable disinfectants or antiseptics. 

But when we are actually dealing with disease germs, 
disinfection, to be trustworthy, must be carried out to 
the best of our ability with the means at our command 
and with strict attention to the minutest details. " There 
can be no partial disinfection of infectious material ; 
either its infectious power is destroyed or it is not. In 
the latter case there is a failure to disinfect." This is 
because the undestroyed living bacteria still have the 
power of reproduction, and may, within a very short time 
under favorable circumstances, equal or even exceed the 
number that was present before the unsuccessful attempt 
at disinfection was made. 

The knowledge as to the efficacy of any substance as a 
disinfectant is obtained from the accumulated experiences 
of practical sanitarians and from experiments on suscep- 
tible animals and in culture media in which infectious 
matter is treated with the substance in question or that is 
being tested. The knowledge gained must stand the test 
of scientific deduction, and a substance is not a disinfect- 
ant simply because, in one given case, infection did not 
occur after its use. To be of value the deductions must 



DISINFECTION AND QUARANTINE. 301 

be made from considerable accumulated and practical ex- 
perience. " Negative evidence should be received with 
great caution f but if the experience of practical sanitar- 
ians is confirmed by careful culture and inoculation 
experiments, our knowledge of the value of any agent 
becomes more definite and our practical work more exact. 
From these inoculations and experiments it has been 
found that the infectious germs of different diseases differ 
in their power to resist the different disinfectants ; but 
nevertheless it may be stated that " in the absence of 
spores, a disinfectant for one is a disinfectant for all." 
Consequently, we are able to simplify and classify the 
agents at our disposal and to make more effectual use of 
them. Note that there is nothing in the tests mentioned 
to disprove the efficacy of disinfectants, whatever the 
nature of the infecting material and whether the germ 
theory be accepted or not. 

Some agents that are powerful against all other organ- 
isms completely fail in destroying the vitality of spores, 
and thus our list of disinfectants available in all cases is 
still further reduced. In the case of a disease germ that 
does not produce spores, as that of cholera, and probably 
also of scarlet fever, smallpox, yellow fever, etc., agents 
may be used that are really powerless against spores, but 
in doubtful cases only those should be used that have the 
power of spore destruction. 

We may classify the disinfectants of which we may 
make practical use as either thermal or chemical, though 
there are undoubtedly certain secretions and tissues in the 
body which have the power of destroying infective mat- 
ters, giving each person more or less immunity against 
certain diseases, and these we may term physiological 
disinfectants. 



302 A MANUAL OF HYGIENE AND SANITATION. 

Of the thermal disinfectants fire is the most efficacious, 
as it destroys all organic matter, but it can only be used 
to destroy articles of little value or that cannot be safely 
disinfected in any other way. For instance, as it will 
usually cost more than they are worth to disinfect thor- 
oughly by other methods old mattresses that have been 
used in an infectious case, it is best to burn them. 

Fig. 46. 




Steam sterilizer for small articles. 



All things considered, steam is probably the most effi- 
cient disinfectant, as it is cheap, easily used and manipu- 
lated, and is less liable to injure the articles to be 
disinfected. We employ it under pressure, when its tem- 
perature is correspondingly increased, or in the streaming 
state (live steam), the latter being almost as efficient as 
the former, but requiring a little longer time. For in- 
stance, steam at 240° F. is said to kill the most resistant 
spores very quickly, and streaming steam at 212° F. will 
produce the same effect within thirty or forty minutes. 






DISINFECTION AND QUARANTINE. 3Q3 



Special apparatus for disinfecting large articles by steam 
is now or doubtless soon will be established in every large 
city and hospital by the municipal authorities and others, 
as a sanitary precaution and to prevent the spread of 
epidemics. 

In steam sterilization, as with all other disinfectants, 
the aim must be to bring the germicidal agent in contact 
with every part of the infected matter ; in other words, 
to secure thorough penetration. The size and compact- 
ness of the articles to be sterilized accordingly govern in 
part the duration of their treatment by the steam. Steam 
under pressure is, of course, more penetrating than live 
steam, and is especially expeditious when the apparatus 
is so arranged that the air can be exhausted from it and 
a vacuum created in the interstices of the articles to be 
disinfected before the superheated steam is introduced. 

In the large sterilizers constructed for hospital or muni- 
cipal use every precaution is taken to prevent the reinfec- 
tion of articles after they have been once sterilized. The 
goods enter the apparatus at one end and are taken from 
it after the treatment at the other, being handled and 
delivered to their owners or destination by an entirely 
different group of employes and conveyances than those 
concerned with them before the disinfection. The appa- 
ratus is built into a closer! partition, which entirety sepa- 
rates the two parts of the disinfecting building and prevents 
any transmission of germs from the infected to the dis- 
infected side, especially as the doors of the sterilizer are, 
or should be, so arranged that they cannot both be open 
at the same time. 

In the absence of spores, bacteria are killed by hol- 
water even below the boiling-point, and it is safe to say 
that boiling for ten or fifteen minutes will kill all known 



304 A MANUAL OF HYGIENE AND SANITATION. 

disease germs, especially if from 1 to 2 per cent, of wash- 
ing soda be added to the water ; although spores of cer- 
tain harmless bacilli are said to have resisted boiling for 
several hours. In the absence of chemical disinfectants, 
boiliug water may be used to disinfect excreta, etc.; and 
all clothing from the sick or the attendants upon the sick 
should be will boiled before washing, whether other disin- 

FlG. 47. 




Steam disinfecting chamber for clothing, bedding and other large articles. 



fectants are used or not. Boiling soda solution is also 
very convenient and effective for the disinfection of sur- 
gical instruments and any apparatus or utensils that the 
sick have used. 

Dry heat is far less penetrating and less effective than 
moist, and must, accordingly, be used at much higher 
temperatures and for a longer time. At 300° F. it will 
require at least three or four times as long to do what 






DISINFECTION AND QUARANTINE. 3Q5 



steam at 212° or 220° F. will do, and, moreover, it is 
very apt to injure clothing or other organic materials ex- 
posed to it at such high temperatures for so long a time 
as is necessary. Consequently, it is only to be used to 
disinfect articles that would be spoiled by moisture or 
chemicals, and even then it is better to employ the " frac- 
tional " method of disinfection — i. e., exposure to high 
temperatures for short periods only, but for a number of 
times, with sufficient intervals between the exposures to 
allow the development of any spores that may possibly be 
present. 

Regarding the chemical disinfectants, it must be remem- 
bered that it requires a certain amount of each to disin- 
fect a given quantity of bacteria, and also that, with all 
disinfectants, time is an important element, as none act 
absolutely instantaneously. Heat, however, facilitates 
and increases the rapidity of action of the chemical disin- 
fectants. 

Another caution to be observed is that the disinfectant 
should always be of sufficient strength in the mixture with 
infected material. For example, if a disinfectant is only 
effective in 1 per cent, strength or more, then at least a 
2 per cent, solution should be added, volume for volume, 
to the matters to be disinfected, and should be thoroughly 
mixed with the latter in order that the germicide may be 
brought into contact with all the infective organisms. 

Chlorinated lime (often called chloride of lime) is one 
of the best and cheapest disinfectants. It should contain 
at least 25 per cent, of available chlorine, should be kept 
covered from air and moisture, and fresh solutions should 
always be made as needed. Its power is due to hypo- 
chlorite of lime, which is freely soluble in water and 
readily decomposes in contact with organic matter, giving 

20 



306 A MANUAL OF HYGIENE AND SANITATION. 

up chlorine gas — a most powerful disinfectant. " Germs 
of all kinds, including the most resistant spores, are 
destroyed by this solution ; but it must be remembered 
that the disinfectaut itself is quickly decomposed and 
destroyed by contact with organic matter, and that if this 
is present in excess, disinfection may not be accomplished, 
especially when the germs are embedded in masses of 
material which are left after the hypochlorite of lime has 
been all exhausted in the solution." Labarraque's 
solution of chlorinated soda is a fair disinfectant, but 
does not keep well, and chlorinated lime is equally as 
good and much cheaper. However, the soda solution has 
scarcely any disagreeable odor, and makes a pleasant dis- 
infecting bath for the person. The official solution must 
contain at least 3 per cent, of available chlorine, but it 
may be diluted with from two to five parts of water 
before use, especially for bathing. 

Though probably effective against sporeless bacteria in 
somewhat less proportions, solutions of chlorinated lime 
should be of at least 1 per cent, strength by weight and 
should be used in excess, to allow for both the dilution 
by the mass to be disinfected and the exhaustion of the 
hypochlorite by organic matter. 

Bichloride of mercury is one of the best germicides that 
we have, and is effective in comparatively weak solutions. 
It corrodes metal, and so cannot be used to disinfect waste- 
pipes, etc. ; and it combines with and coagulates albumin, 
which interferes somewhat with its action. This coagu- 
lation is prevented to a degree by the addition of a small 
amount of tartaric acid to the disinfecting liquid. The 
same result is said to be obtained if one part of peroxide 
of hydrogen (fifteen volume solution) be added to three 
parts of a corrosive sublimate solution of any strength, or 



DISINFECTION AND QUARANTINE. 307 

by adding common salt (0.5 to 1 per cent.) to the solution. 
But for the above reason it is best not to use corrosive 
sublimate in disinfecting excreta, as these always contain 
more or less albumin, and a lime solution is better and 
more certain. As carbolic acid also coagulates albumin, 
it is not well to use it for a like purpose. 

Bichloride of mercury should be used in solutions of 
from 1 in 1000 to 1 in 5000 strength for ordinary disin- 
fection, though weaker preparations are sometimes used 
in surgical cases. It is especially valuable where a large 
amount of fluid is to be freely used, but the solutions 
should always be colored by a little aniline dye or copper 
sulphate, on account of its poisonous properties, and the 
consequent danger from its lack of color. Abbott cau- 
tions that the stains of blood and feces on clothing are 
rendered almost indelible by long soaking in bichloride 
solutions. Silver nitrate is almost, if not fully, as good 
a disinfectant as bichloride of mercury, and does not 
coagulate albumin so readily, but is much more expensive. 

Carbolic acid is effective in the absence of spores, and, 
according to Koch, should have first place in disinfection 
against the cholera germ. It is of doubtful value, how- 
ever, in cases of typhoid fever, as it is said that the 
typhoid bacilli can be cultivated in a medium containing 
0.5 per cent, of carbolic acid. Solutions should always be 
made by first dissolving the acid in hot- water, and should 
contain from 2 to 5 per cent, of acid, the latter being 
practically a saturated solution. The stronger solution is 
especially valuable for the direct disinfection of human 
excreta of all kinds, but must be thoroughly mixed with 
the same, while the weaker fluid (2 or 3 per cent.) may 
be used freely for the disinfection of clothing or the wash- 
ing of walls, floors, furniture, etc. 



308 A MANUAL OF HYGIENE AND SANITATION. 

A 2 or 3 per cent, solution of a mixture of equal parts 
of carbolic and sulphuric acids is valuable for the disin- 
fection of water-closets, urinals, etc., as the latter acid 
increases the effectiveness of the mixture ; but it must not 
be kept too long in contact with metals on account of the 
corrosive action of the sulphuric acid. 

Solutions of the cresols (meta-, para- and ortho-), which 
are derived from coal- or wood-tar, and much resemble car- 
bolic acid, may be used for the same purposes and in about 
the same strength as solutions of the latter. In fact, tricre- 
sol, which is a refined combination of the three, is two or 
three times as powerful a disinfectant as carbolic acid, and, 
in solutions of from 0.5 to 1 per cent, strength, makes an 
agreeable and efficient disinfectant for use in surgery and 
obstetrics, especially as it does not coagulate albumin as 
readily as do carbolic acid and corrosive sublimate. As 
carbolic acid and cresol solutions are all poisonous, they 
should always be so labelled, although the characteristic 
odor serves as a partial safeguard to those accustomed to it. 

Oreolin is another coal-tar product that has decided 
germicidal power. Being cheap, it can be used freely 
for disinfectiug drains, stables, urinals and such places 
where its rather strong odor is not objectionable. It 
should be made up in from 2 to 5 per cent, strength in 
water, and, being insoluble, the mixture must be thor- 
oughly stirred or shaken each time before use. 

Zinc chloride is a good antiseptic and deodorant, but 
not a very powerful disinfectant. A 5 or 10 per cent, 
solution will kill germs without spores. 

Calcium hydrate, when mixed with water to make a 
thin whitewash (milk of lime), is said to be a good disin- 
fectant, especially for excreta, etc., and is one of the 
cheapest and easiest to obtain. It should be added to the 



DISINFECTION AND Q UARANTINE. 309 

infectious matter in excess or until the mixture is decidedly 
alkaline, and will require from one to two hours to disin- 
fect thoroughly. 

The proportion of lime to water should be about as 1 to 
4, equal parts being first taken to allow the slaking of the 
lime, and the rest of the water then added and the mass 
thoroughly mixed by stirring. Two quarts of this mixt- 
ure per day for each person using a cesspool will keep the 
contents of the latter disinfected and free from putrefac- 
tive odors, provided its use commences with the use of the 
cesspool, or that the prior contents have been disinfected 
by an excess of this or a chlorinated lime solution, or by 
an abundance of the latter salt or quicklime in powder. 

Sulphate of iron, which acts as an antiseptic to prevent 
putrefaction, rather than as a disinfectant, may also be 
added to the contents of an offensive or dangerous cess- 
pool to the extent of about four pounds for each cubic 
yard of the mass. The sulphate should, of course, be 
thoroughly dissolved before using. 

An extremely valuable disinfectant for local or topical 
applications to the person is hydrogen peroxide or dioxide 
(H 2 2 ). It is harmless, even when taken internally ; is 
effective in comparatively weak solutions, and is especially 
active in the destruction of pus organisms. It is usually 
supplied in the form of a 15 per cent, solution in water 
and, at present, only its high cost prevents its more ex- 
tended use. 

Until the discovery, in 1892, of the great disinfecting 
power of formaldehyde or formic aldehyde by Trillat and 
Aronson, about the only gaseous disinfectants of practical 
value were chlorine and sulphur dioxide. 

Of these, chlorine is the most powerful and efficient, 
but the distressing and oftentimes serious symptoms which 



310 A MANUAL OF HYGIENE AND SANITATION. 

it produces when accidentally inhaled, and the bleaching 
effect that it has upon many articles, have both tended to 
prevent its common employment. Like the sulphur 
dioxide, it acts best in the presence of moisture, and, 
therefore, steam should be simultaneously introduced and 
liberated in the room or enclosure in which either of these 
disinfectants is used. Sufficient chlorine for 1000 cubic 
feet of space may be generated by carefully pouring two 
fluidounces of strong sulphuric acid and three fluidounces 
of water, previously mixed and cooled, upon eight ounces 
of sodium chloride (common salt) and two ounces of man- 
ganese dioxide. The acid must be added to the water 
little by little and with care, and the salt and manganese 
should be in an earthen vessel upon a bed of sand, to pre- 
vent injury to the floor or carpet. Moreover, as the 
chlorine gas is very heavy, the generating apparatus should 
be at as high a level as possible in the room to get even 
fair diffusion. 

Sulphur dioxide (S0 2 ), though not so positive in its 
action as chlorine, is more frequently employed on account 
of the lesser risk and trouble connected with it. It prob- 
ably kills germs not containing spores if sufficiently con- 
centrated and in the presence of moisture, and is, therefore, 
useful in the fumigation of rooms and of articles that can- 
not be subjected to steam heat or chemical solutions. But 
it will bleach or tarnish many articles, and for this reason 
and the fact that it is much inferior to formaldehyde, it 
will hereafter probably be almost entirely supplanted by 
the latter whenever that can be obtained. 

To secure sufficient concentration at least three pounds 
of sulphur should be burned for every 1000 cubic feet of 
air-space, care, of course, being taken that there may be 
no risk of igniting the floor or any articles in the room. 



DISINFECTION AND QUARANTINE. 31 1 

Before the fumigation of a room with chlorine or sul- 
phur dioxide, or with formaldehyde, all apertures and 
crevices in the walls, ceiling or floor should be carefully 
closed from the outside, to maintain the gases in as con- 
centrated a state as possible during the process, which 
should continue for at least twenty-four hours in the case 
of chlorine or sulphur gas, and for not less than six hours 
with formaldehyde. After the fumigation, the room should 
be thrown open and well ventilated, and then thoroughly 
cleansed with a corrosive sublimate, carbolic acid or hot 
soda solution, a 4 per cent, solution of the latter being not 
only cleansing, but strongly disinfectant as well. 

Formaldehyde (formic aldehyde), both in its gaseous 
state and in solution, is undoubtedly one of the best and 
most efficient disinfectants now in use. It has consider- 
able penetrating power, although less than steam or than 
was claimed for it at first by its more enthusiastic advo- 
cates, while for surface disinfection it acts almost imme- 
diately. It is, therefore, much better in this respect than 
the chlorine or sulphur dioxide already mentioned, and 
where it is properly used, only such articles as bedding, 
mattresses and pillows, that can be better treated with 
steam, need be removed from an infected apartment. 
Clothing, rugs, hangings, etc., that can be freely exposed 
to it are quickly sterilized. Another important feature is 
that it does not bleach nor act destructively on either 
clothing or furniture, and that, although it is quite 
irritating to the conjunctivae of the eyes and to other 
mucous membranes when concentrated, it is virtually non- 
poisonous. 

Formaldehyde is readily absorbed and held in solution 
by water to the extent of 40 per cent, by weight of the 
latter, but as soon as this proportion is exceeded there is 



312 A MANUAL OF HYGIENE AND SANITATION. 

a polymerization of the gas and a solid (paraformaldehyde 
or paraform) is precipitated, which is only resolved again 
into formaldehyde at a temperature of 275° F. The 40 
per cent, solution is practically identical with the prepara- 
tion which is commercially known as formalin, which has 
usually an addition of 10 per cent, of methyl alcohol to 
further guard against precipitation. Very weak solutions 
(1 or 2 per cent.) of the gas are still effectively disinfect- 
ant, while its virtue as an antiseptic persists even when 
the dilution is carried to a remarkable degree. 

One peculiar effect of the solutions is that of rendering 
connective tissue and all gelatinous substances insoluble 
in either hot or cold water, and it is probably to this that 
its germicidal activity is largely due, since the food-supply 
of the bacteria, if not the substance of the latter them- 
selves, is partly of this nature. For the same reason it 
hardens and disagreeably roughens the skin, which tends 
to prevent its use for topical applications to the human 
body. 

Several methods have been devised for the production 
or liberation of formaldehyde in rooms and buildings in 
such volume as positively to secure both surface and pene- 
trative disinfection. Of these, the best results seem to 
have been obtained where a solution of the gas, such as 
formalin or formochloral (the latter a mixture of the 
former with calcium chloride), is heated and vaporized. 
For instance, in Trillat ? s apparatus the latter solution is 
used, the calcium chloride being added to further ensure 
against the precipitation of paraform. A simpler device, 
called a regenerator, allows the formalin to flow in a fine 
stream through a copper coil heated to redness by a flame 
beneath, the gas and vapor then passing directly into the 
room in a superheated and effective condition. Both of 



DISINFECTION AND QUARANTINE. 



313 



these methods have the advantage that the apparatus may 
be operated outside of the room to be disinfected, and the 
action accordingly controlled ; also that the amount of gas 
liberated depends directly upon the strength and quantity 
of the solution evaporated. 

In the Schering method the solid paraform is heated 
in a receptacle over an alcohol lamp, the volume of re- 
sulting formaldehyde depending, of course, upon the 
amount of paraform used. This method has yielded some 



Fig. 48. 



Fig. 49. 





Trillat's autoclave or apparatus for 
liberating formaldehyde. 



Regenerator for vaporizing for- 
maldehyde solutions. 



excellent results experimentally, and is of special value 
in disinfecting small rooms, closets and sterilizing cases 
made for instruments, dressings, etc. 

Probably the cheapest and formerly the most common 
form of apparatus is that which has been devised, in the 
form of a portable lamp, to develop the gas directly by 
the oxidation of methyl alcohol, the vapors of the latter 
being made to pass over or through tubes or coils of heated 
metal, and to be thus converted into the disinfectant gas. 



314 A MANUAL OF HYGIENE AND SANITATION. 

Considerable formaldehyde can doubtless be produced in 
this way, but the amount at any time is uncertain and 
the results indefinite, since part of the alcohol vapors are 
polymerized and part are further oxidized into compounds 
such as carbon monoxide and carbon dioxide. Therefore 
this method is only to be advised for comparatively small 
apartments or enclosures, and not where certainty of dis- 
infection is important. 



Fig. 50. 



Fig. 51. 





Schering's lamps for volatilizing paraform. 

Abbott states that he has " obtained the most satisfac- 
tory results through the use of formalin to which 10 per 
cent, of glycerin has been added, as recommended by 
Schlossmann; and through the employment of a generator 
after the plan of that advised by Xovy and Waite. In 
these tests we found that 80 per cent, of all exposed in- 
fected objects in a room could be disinfected when 500 c.c. 
of the formalin-glycerin mixture per 1000 cubic feet of 
air-space was completely evaporated and the room kept 
closed for three or four hours." 1 

In the other apparatus one pound of formalin or formo- 



1 Hygiene of Transmissible Diseases, 1899, p. 269. 



DISINFECTION AND QUARANTINE. 



315 



chloral, from 50 to 75 of Sobering' s paraforrn tablets, or 
a quart of methyl alcohol are to be respectively used for 
each 1000 cubic feet of air-space to be disinfected. 1 

Whenever formaldehyde is employed as a gas all the 
apertures in the room should be carefully and tightly 



Fig. 52. 




Modified Novy-Waite formaldehyde generator. 

closed, since, having the same specific gravity as the air, 
its diffusion takes place rapidly. Moreover, after a suffi- 
cient volume of the gas has been liberated, it should be 
allowed to act as long as possible, preferably for six or 
eight hours at least, since, though it is more rapid, the 

1 See also U. S. Quarantine Regulations, pp. 292, 293. 



L 



316 A MANUAL OF HYGIENE AND SANITATION 



time element is just as important a factor with this as 
with other disinfectants. 

Lastly, the gas is an excellent deodorant, combining as 
it does with the effluvia from decomposing substances to 
produce odorless compounds. Its odor, in turn, may be 
quickly dissipated from a room by evaporating a little 
ammonia therein. 

The following table of Koch and Jaeger is added to 
show the comparative disinfectant strength of some sub- 
stances occasionally used for the purpose : 



Disinfectant. 
Bichloride of mercury- 
Silver nitrate . . . . 

Acid, hydrochloric . . 
Acid, sulphuric 

Ferrum chlorate . . . 
Calcium chloride . . 
Potass, permanganate 



Strength. 

1 to 20,000 
1 to 1,000 

1 to 12,000 



•{ 



Caustic lime 



Acid, carbolic . 



Formaldehyde 
(K. Walter.) 



io. 



lto 

lto 

2 to 

2 to 
15 to 

5 to 

5 to 

5 to 

0246 to 
0074 to 

3 to 



10 to 



r 



lto 



M 3 to 



4,000 
2,500 

100 

100 
100 

100 
100 
100 
100 
100 

1,000 

100 
100 
100 



Objects submitted 
to experiments. 

Anthrax spores 
Anthrax spores 

Anthrax spores 
Cholera and typhoid 
Diphtheria 

Anthrax spores 
Anthrax spores 
Anthrax spores 

Anthrax spores 

Anthrax spores 

Anthrax spores 

Cholera 
Typhoid 



Time required 
for destruction. 

10 minutes. 

1 minute. 

70 hours. 

2 hours. 
2 hours. 

10 days. 

53 days. 
8 days. 

6 days. 

5 days. 
1 day. 

6 hours. 
6 hours. 



Staphylococcus and ) g _ n seconds> 
streptococcus pyog. J 
Anthrax spores 24 hours. 

J Nearly all patho- \ Less than 
t genie germs > 30 minutes. 

Anthrax spores 15 minutes. 

All other patho- j x minute- 



genie germs 

In any case of infectious disease special attention should 
be given to disinfecting the excretions and secretions 
which are known to be most likely to contain the disease 
germs, viz., the desquamating epithelium and likewise 
the renal secretion in measles, scarlet fever and all the 
exanthemata ; the dejecta in typhoid fever, cholera, 



DISINFECTION AND QUARANTINE. 317 

tropical or infectious dysentery, and in tuberculosis of 
the intestinal or genito-urinary tract ; the sputum in 
tuberculosis of the lungs and air-passages, and in in- 
fluenza, pneumonia and diphtheria ; secretions from the 
throat and nose in diphtheria, scarlet fever and measles ; 
discharges from abscesses, suppurating or gangrenous 
wounds, etc. 

During the course of the illness there should be no more 
communication than is absolutely necessary between the 
occupants of the sick-room and those in the rest of the 
house, and a sheet should be hung at the door and kept 
moist with some disinfecting solution, as this will largely 
prevent the escape of infected dust particles through 
the doorway. All articles going from the room, whether 
dishes, clothing or food, should be submerged in a disin- 
fectant or covered with a cloth wet with it, and should be 
burned, boiled or otherwise disinfected as soon as possi- 
ble thereafter. Excreta should be disinfected as soon as 
discharged from the body, but should not be emptied into 
a water-closet, sewer or cesspool till the disinfectant has 
had ample time to do its work, at least one hour being 
given for this action. Ventilation should be as perfect 
as possible ; sunlight should be admitted whenever it will 
not injure or annoy the patient, and, above all, cleanliness 
in every respect should be insisted upon as being most 
essential. 

The dress of the nurse or attendant should be such 
that dust and germs do not readily adhere to it and that 
it may readily be disinfected and cleaned, the cotton 
uniforms of a hospital training school being almost ideal 
in this respect. If this were in the form of an overgar- 
ment that could readily be slipped off when the nurse has 
to leave the sick-room, there would be an additional 



318 A MANUAL OF HYGIENE AND SANITATION. 

element of safety, just as there will be if there is provided 
something like a long, old-fashioned linen " duster' 7 for 
the casual visitor, whether physician or parent, to slip on 
when they enter the room. The nurse should, of course, 
bathe not only the patient but herself with disinfectant 
solutions, such as Labarraque's (diluted), carbolic acid or 
tricresol; should destroy at once all possible infection 
coming from the patient, and at least every other day 
should wipe with a cloth dampened in a disinfectant all win- 
dow-sills, tables and other horizontal surfaces upon which 
dust and the attached germs continually settle. A closet 
with a close-fitting door may be made to serve as a good 
disinfecting chamber for garments that are not in imme- 
diate use, as a few ounces of formalin sprinkled on the 
garments themselves or a few paraform tablets burned in 
one of the Schering lamps will quickly sterilize the con- 
tents of the closet without serious discomfort to the occu- 
pants of the adjoining room. 

It is taken for granted , that, if possible, before the 
occupancy of the room by the sick, all upholstered furni- 
ture, heavy drapery and everything not absolutely neces- 
sary were removed from the room. Even the carpet 
should be taken up and rugs used temporarily in its place. 
If this is done, the work of disinfecting the room after it 
is no longer needed by the patient will be greatly facili- 
tated. 

Where the use of formaldehyde is not available, the 
final disinfection should be carried out as follows : All 
bedclothing, etc., should be either submerged in some 
disinfectant solution or in boiling water, or else covered 
with a sheet wet with a disinfectant, and boiled as soon 
as possible thereafter. No clothing should be sent away 
from the house to be laundered. Bedquilts, blankets, 



DISINFECTION AND QUA BANTINE. 31 9 

mattresses, etc., should be subjected to steam sterilization 
if possible ; if not, the blankets and quilts should be 
carefully sterilized by boiling, and the mattresses would 
better be burned. The carpet or rugs should be carefully 
taken up, carried to an open space, well beaten, and then 
hung in the open air for a time, provided they cannot be 
sent at once to some place where steam sterilization is 
available. All furniture and the woodwork of the room 
should be washed with corrosive sublimate solution (1 to 
500 or 1000), taking care to get the fluid into all crevices. 
The floor may be scrubbed with lye or hot soda solution 
(4 per cent.), and then mopped and flooded with a corros- 
ive sublimate solution. The walls should also be wiped 
with cloths wrung out of this solution and any paper upon 
them removed before fumigation, unless it be new and 
free from cracks. Or the walls may be rubbed down 
with crumbs of bread and the latter burned, as the 
bread contains much gluten, to which the dust and bac- 
teria adhere. Fumigation will scarcely be necessary, and 
is usually of somewhat doubtful efficiency. If it is em- 
ployed, it should be done first, before the bedding, etc., 
is removed and the walls, floors, woodwork are wiped or 
washed, and all openings from the room, cracks, crevices, 
etc., should be closed on the outside, and sufficient gas 
(chlorine or sulphurous acid) liberated by suitable means. 
The vessels containing the gas-generating substances should 
be placed in larger vessels containing water to avoid the 
danger of fire, and vapor of water should be liberated in 
some way simultaneously with the gas, say by placing 
hot bricks or the like in the water, or else water should 
be sprayed freely from an atomizer over everything in the 
room, as neither chlorine nor sulphurous acid has much 
disinfecting value except in the presence of moisture. 



320 ^ MANUAL OF HYGIENE AND SANITATION 

The room should then remain closed for twenty-four hours 
and, lastly, should be well ventilated for a day or two 
before being furnished and occupied again. 

Should it be possible to use formaldehyde, the disinfec- 
tion is much simplified, and is to be carried out in the 
way already indicated, but it should be always followed 
by the washing or wiping of walls, ceilings, floor and all 
exposed surfaces with a disinfectant solution, and by the 
steam sterilization or boiling of all removable articles 
wherever possible. In fact, it should be remembered that 
no one of these processes will in any probability destroy 
all the infection, but that each must be carried out with 
conscientious thoroughness and strictest attention to detail 
in order to secure the greatest chance of success. 

Quarantine. 

Quarantine may be described as the methods and meas- 
ures imposed by a government — local, State, or national 
— to prevent the introduction of infectious disease into the 
country or from one locality to another. Although the 
term in itself is misleading, being derived from the 
Italian " quarante" (forty), and signifying the period 
of detention of the first Venetian quarantines, it is now 
generally taken to indicate the entire routine of inspec- 
tion, disinfection and detention, without regard to the 
length of time involved. 

While all civilized nations have from the earliest times 
recognized the importance of separating those afflicted 
with epidemic disease from the well, the development of 
the idea and practice of quarantine has necessarily been 
consequent upon the growth of commerce ; and while 
there had practically always been isolation for leprosy, 
the first quarantine enactments, in our meaning of the 



J 






DISINFECTION AND QUARANTINE. 321 



term, were put in force in Venice about the beginning of 
the fifteenth century as a barrier to both the black and 
the Egyptian plague. Then it was realized that epidemic 
diseases were transmitted by those attacked, a bureau of 
health and a lazaretto were established, the effects of 
those who died of the plague were destroyed, and the 
period of detention of incoming vessels, passengers and 
cargoes was fixed at forty days, the idea being that this 
period was in itself more or less mystic and salutary. 

As time went on and the plague spread over the whole 
of Europe, the number of lazarettos was largely increased, 
especially in the eighteenth century. Of these, the one 
at Marseilles became the most noted, not only because it 
was located at one of the most important ports of the 
Mediterranean, but because of its excellent care and man- 
agement. Thanks to the increased efficacy of quarantine 
and other sanitary regulations, as the knowledge concern- 
ing them developed, the plague rapidly subsided soon 
after the beginning of the present century, and interest 
in it was supplanted by that in relation to the frequent 
epidemics of cholera and yellow fever that began to alarm 
the civilized world, and it is to prevent the ingress of 
these latter diseases, together with leprosy, smallpox and 
typhus fever, that the present quarantine regulations are 
in the main devised. 

With the knowledge already gained regarding the 
nature and causes of infectious diseases, their periods of 
incubation, etc., it is at once evident that it will be 
neither necessary nor wise to fix upon a prolonged and 
arbitrary time during which vessels or passengers must 
be detained in quarantine. All that is needed is that the 
proper inspecting officers shall be satisfied that there is no 
danger of contagion entering the country, and, where any 

21 



322 A MANUAL OF HYGIENE AND SANITATION. 

detention is necessary, it is only for so long as will suffice 
for the disinfection of the vessel, cargo and passengers' 
effects, and to cover the period of incubation of the sus- 
pected disease. 

The present quarantine laws of the United States, and 
the latest regulations of the Treasury Department based 
upon them, are especially designed to afford the greatest 
possible protection to the country against the importation 
of disease with the least possible detention of incoming 
vessels and passengers. An important innovation that 
facilitates both these ends has been the establishment of 
quarantine in foreign lands, as it were, viz., the inspec- 
tion and, if necessary, disinfection by officers of this gov- 
ernment of all vessels, passengers and cargoes leaving a 
foreign port for any port of the United States. This 
undoubtedly greatly diminishes the danger of the intro- 
duction of any contagious disease ; but, in addition, there 
is that section of the law that provides that the President 
may, whenever the condition of affairs shall seem to war- 
rant it, u prohibit, in whole or in part, the introduction 
of persons and property from such countries or places as 
he shall designate and for such period of time as he shall 
deem necessary. " 

Accordingly, every vessel clearing from a foreign port 
for this country must obtain from the United States con- 
sular officer of the port, or from the medical officer ap- 
pointed for the purpose, a bill of health, " setting forth 
the sanitary history and condition of said vessel, and that 
it has in all respects complied with the rules and regula- 
tions in such cases prescribed for securing the best sani- 
tary conditions of the said vessel, its cargo, passengers, 
and crew." Before signing the bill of health the consular 
or medical officer must be satisfied that the conditions 






DISINFECTION AND QUARANTINE. 323 

certified to therein are true, and must personally inspect 
" all vessels from ports at which cholera prevails, or at 
which yellow fever, smallpox, or typhus fever prevails in 
epidemic form/' and " all vessels carrying steerage pas- 
sengers." Moreover, the vessel must be clean in all 
parts before taking on either passengers or crew, and all 
parts liable to infection must be disinfected if any infec- 
tious disease has occurred on the last voyage. The bedding 
provided for steerage passengers must also be destroyed or 
else disinfected before being used on another voyage. 

The regulations also indicate what kind of cargo, com- 
ing from or through infected districts, may or may not be 
shipped, and what kinds must invariably be disinfected 
under any circumstances. 

As to the passengers, while they are divided into two 
classes, cabin and steerage, no person suffering from 
cholera, smallpox, yellow or typhoid fever, scarlet fever, 
measles, or diphtheria is allowed to ship ; nor should 
passengers ship from an infected port. Steerage passen- 
gers and crew who have been exposed to smallpox must 
be vaccinated before shipping unless they can show proof 
of immunity by former attack or satisfactory vaccination. 
If the steerage passengers and crew have been exposed to 
typhus fever infection they may not embark until four- 
teen days after such exposure and the disinfection of their 
baggage, while steerage passengers from cholera infected 
districts must be detained in suitable quarters for five 
days, " the said period to begin only after the bathing of 
the passengers, disinfection of all their baggage and 
apparel, removal of all food brought with them, and 
isolation from others not so treated." The same rules as 
to detention and disinfection are to be applied to those 
coming from places where the plague, yellow fever or 



324 ^ MANUAL OF HYGIENE AND SANITATION. 

smallpox is prevalent in an epidemic form, and if one of 
these diseases or cholera breaks out in the detention bar- 
racks there must be a repetition of the five-days' isolation, 
disinfection, etc., dating from the removal of the last 
case. Cabin passengers from cholera or other infected 
ports or districts should produce satisfactory evidence as 
to their place of abode for the five days immediately pre- 
ceding embarkation, and if there is any reason for the 
belief that any one of these or his baggage has been in- 
fected, such passenger is to be detained as long as the in- 
specting officer may deem wise, and his baggage is to be 
disinfected. 

Every passenger must also have an inspection-card, 
stamped by the consular or medical officer, giving name 
of passenger, and of ship and port with date of departure, 
etc. ; and all baggage of passengers must have a label 
bearing the seal or stamp of the United States consular 
or medical officer, the name of port and of the vessel car- 
rying the baggage, and the statement and date of inspection 
or disinfection. 

It is evident that if these regulations at foreign ports, 
together with those required at sea — viz., rigorous clean- 
liness and free ventilation of the vessel, daily inspection 
by the ship's physician, isolation and disinfection of the 
sick, etc. — be properly observed, there can be but little 
chance of the germs of quarantinable disease gaining en- 
trance to our country, and, since the duration of the voy- 
age will in most cases exceed the period of incubation of 
most of the contagious diseases, if none of these manifest 
themselves on shipboard at sea there will be no need for 
any detention at the port of entry beyond that which the 
inspecting officer stationed there requires for the perform- 
ance of his duties, viz., to inspect the vessel, bill of 



DISINFECTION AND QUARANTINE. 325 

health, crew and passengers, and their lists and manifests, 
the ship physician's clinical record of all cases treated, 
and, when necessary, the ship's log. 

This inspection service is to be maintained at every 
port throughout the year, and is in force not only with 
respect to all vessels from foreign ports, but regarding 
any vessel with sickness on board, vessels from domestic 
ports where cholera or yellow fever prevails, or where 
smallpox or typhus fever prevails in epidemic form, ves- 
sels from foreign ports carrying passengers having entered 
a port of the United States without complete discharge of 
passengers or cargo, and vessels having been treated at 
national quarantine stations that are located a considerable 
distance from the port of entry of said vessels. More- 
over, the duties of the inspecting officer above stated are 
only the required minimum standard, and such other 
regulations may be added by legal State or local authori- 
ties as may, for special reasons, be necessary. 

If the inspecting or health officer is satisfied that the 
vessel is not infected and all the foregoing requirements 
have been complied with, he gives his certificate, to be 
delivered to the collector of customs of the port, and no 
vessel is permitted to land any of its passengers or cargo 
unless it have this certificate, together with the bill of 
health, etc., from the port of departure, as evidence that 
the regulations have been properly observed. 

On the other hand, if vessels arrive under the follow- 
ing conditions they are to be remanded by the authority 
of the Secretary of the Treasury to the nearest national 
or other quarantine station, where proper accommodations 
and appliances are provided for the necessary disinfection 
and treatment of the vessel, passengers and cargo ; and 
only after treatment and after obtaining a certificate from 



326 A MANUAL OF HYGIENE AND SANITATION. 

the proper officer that the vessel, cargo and passengers are 
each and all free from infectious disease and from danger 
of conveying the same, can a vessel be admitted to entry 
to the ports named in the certificate. 

The conditions under which arriving vessels are to be 
placed in quarantine are these : " A. With quarantine 
disease on board, the quarantinable disease for the pur- 
poses of these regulations being cholera (cholerine), yellow 
fever, smallpox, typhus fever, and leprosy. B. Having 
had such on board during the voyage or within thirty 
days next preceding arrival ; or, if arriving in the quar- 
antine season, having had yellow fever on board after 
March 1st of the current year, unless satisfactorily disin- 
fected thereafter. C. From ports infected with cholera 
or where typhus fever prevails in epidemic form, coming 
directly or via another foreign port, or via United States 
ports, unless they have complied with the United States 
quarantine regulations for foreign ports ; also vessels 
from non-infected ports, hut bringing persons or cargo 
from places infected with cholera, yellow fever, or where 
typhus fever prevails in epidemic form, except as subse- 
quently noted. D. From ports where yellow fever pre- 
vails, unless disinfected in accordance with these regula- 
tions, and not less than five days have elapsed since such 
disinfection. 

" The following exceptions may be made to Rules C. 
and D. with regard to vessels quarantined against on 
account of yellow fever : (1) Vessels arriving from 
November 1st to May 1st may be admitted to entry. 
(2) Vessels bound for ports in the United States north of 
the southern boundary of Maryland, with good sanitary 
condition and history, having had no sickness on board 
at ports of departure, en route or on arrival, provided 



DISINFECTION AND QUARANTINE. 327 

they have been five days from last infected or suspected 
port, may be allowed entry at port of destination. But 
if said vessels carry passengers destined for places south 
of this latitude the baggage of said passengers shall be 
disinfected, and such baggage shall be labelled. (3) Ves- 
sels engaged in the fruit trade from ports declared safe for 
this purpose by the Supervising Surgeon-General of the 
Marine Hospital Service may be admitted to entry with- 
out detention, provided they carry no passengers and have 
carried no passengers from one port to another, and have 
no household effects or personal baggage in cargo, and 
have complied with the rules and regulations made by the 
Secretary of the Treasury with regard to vessels engaged 
in said trade." 1 

Moreover, all passengers other than those occupying 
first or second cabin, and all persons arriving on vessels 
that have had smallpox on board, must be vaccinated 
or detained in quarantine not less than fourteen days, 
unless they can show satisfactory evidence of recent vac- 
cination or of having had smallpox ; and all effects and 
compartments liable to convey infection must be disin- 
fected. 

" No case of leprosy will be landed, and vessels arriv- 
ing at quarantine with leprosy on board shall not be 
granted pratique until the leper with his or her baggage 
has been removed from the vessel to the quarantine sta- 
tion. If the leper is an alien passenger and from a 
foreign port, action will be taken as provided by the im- 
migration laws and regulations of the United States. If 
the leper is an alien and a member of the crew, and the 
vessel is from a foreign port, said leper shall be detained 

1 Quarantine Laws and Regulations of the United States. 



328 A MANUAL OF HYGIENE AND SANITATION. 

at quarantine at the vessel's expense, until taken aboard 
by the same vessel when outward bound." 1 

There are ten national quarantine stations and a number 
of others under State or municipal control ; those which 
have steam disinfection chambers and other efficient 
equipments are located at Portland, Me.; Boston, New 
York, Sandy Hook, Delaware Breakwater, Reedy Island 
in the Delaware River, Cape Charles, Baltimore ; Wil- 
mington, N. C. ; Savannah, Blackbeard Island, Ga. ; 
Charleston, Dry Tortugas, Key West, Mullet Keys, Pen- 
sacola, Mobile, Chandeleur Islands, New Orleans, Gal- 
veston, San Diego, San Francisco, and Port Townsend ; 
the ten national ones being included in the list. 

The essential requisites for a properly equipped quaran- 
tine station, after the selection of a proper location — which 
should be convenient, but not in the line of future city 
growth —are the following: 2 1. A boarding station, in- 
cluding boat-house and boatmen 7 s quarters. 2. A board- 
ing-boat, preferably a steamer. 3. An anchorage for the 
detention of infected vessels. It should be safely out of 
the track of commerce, convenient but not too close to the 
main quarantine establishment, sheltered, and with good 
holding ground for anchors. 4. A fumigation steamer 
with appliances for generating and forcing sulphurous- 
acid (or formaldehyde) gas into vessels, and with tanks 
and pumps for disinfecting solutions. 5. A wharf, in 
water at least twenty feet deep, and upon which are con- 
structed a warehouse, tanks for disinfecting solutions, and 
a disinfecting house containing steam disinfecting cham- 
bers. 6. A lazaretto or hospital for the treatment of 
contagious diseases. 7. A hospital for non-contagious 

1 Quarantine Laws and Regulations of the United States. 

2 Robe's Hygiene. 



DISINFECTION AND QUARANTINE. 329 

diseases. 8. Barracks or quarters for the detention in 
groups of those who may have been exposed to contagion 
or infection. 0. Quarters for medical officers. 10. A 
cremation furnace. 

When a vessel is remanded to quarantine by the in- 
specting officer at a port of entry, its treatment and that of 
its cargo and passengers will depend largely upon the dis- 
ease with which it is infected, being more severe if the 
latter is cholera or yellow fever. In case of infection by 
either of these diseases, the vessel is at once sent to the 
anchorage, and must remain there until the passengers 
have been discharged and the vessel purified, and in any 
case there must be no direct communication allowed be- 
tween quarantine or a vessel in quarantine, and any per- 
son or place outside. 

Moreover, if cholera has occurred on board, all passen- 
gers and all of the crew, except such as are necessary to 
care for her, must be at once removed, the sick to be sent 
to the lazaretto or hospital, others specially suspected 
must be carefully isolated, and the remainder separated 
into small groups, between which there must be no com- 
munication. Those who are especially liable to convey 
infection must be bathed and furnished with sterile cloth- 
ing before entering the barracks, and no articles capable 
of carrying infective matter, especially food, should be 
taken into the barracks. If the disease has occurred in 
the steerage, all the steerage passengers must be bathed 
and their clothing disinfected ; and in any case all steerage 
baggage and effects, and any other baggage, etc., that has 
been exposed to the infection, all articles of the cargo 
likely to be infected, and all furniture, living apartments, 
and such other portions of the vessel as may possibly re- 
tain or convey infection must be disinfected. The water- 






330 A MANUAL OF HYGIENE AND SANITATION. 

supply must be changed at once, the tanks thoroughly 
disinfected by steam or permanganate of potash solution, 
and refilled with water from a pure source or with water 
recently boiled. The water-ballast of a cholera-infected 
vessel, or of one from a cholera-infected port, should 
never be discharged in fresh or brackish water without 
previous disinfection, and the ballast-tanks should be re- 
filled with sea-water or else be disinfected before refilling. 
Nothing is to be thrown overboard from a cholera- 
infected vessel in quarantine, but everything that is to be 
destroyed, even deck-sweepings, should be burned in the 
furnace. 

The disinfection of the holds of vessels is to be by 
mechanical cleansing, by an acid bichloride of mercury 
solution (1 to 800) applied under pressure, and by sul- 
phurous-acid gas (10 per cent, per volume strength), for 
from twenty-four to forty-eight hours. All ballast must 
be discharged or disinfected before the disinfection of the 
hold, and all solid ballast must be disinfected before being 
discharged into fresh water. The steerage and forecastle 
are to be disinfected by live steam, if possible, for at least 
half an hour, and, if not, by sulphur dioxide and bichlo- 
ride solution, as was the hold. Baggage, bedding, 
carpets, etc., are to be removed with caution and to be 
disinfected by steam or by boiling, and, finally, all wood- 
work of the vessel is to be thoroughly cleansed mechan- 
ically and then washed with an acid bichloride of mercury 
solution (1 to 1000). 

Under date of August 5, 1897, the Secretary of the 
Treasury issued a circular to State and local quarantine 
authorities " amending Article 5 of the quarantine regu- 
lations to be observed at ports and on the frontiers of the 
United States, by adding two paragraphs, 8 and 9. 



DISINFECTION AND QUARANTINE. 331 

" Disinfection of steerage, forecastle, and cabin of vessels 
by formaldehyde gas. After the removal of the bedding, 
carpets, and furnishings, all apertures being tightly closed, 
the steerage, forecastle, and cabin of a vessel may be dis- 
infected by formaldehyde gas in a percentage of not less 
than 2 per cent, per volume strength, the time of expos- 
ure to be not less than twelve hours. The gas may be 
generated by the following method : 

u From an aqueous solution, containing 40 per cent, of 
the gas, known under the names of formaldehyde, formol, 
or formolose. The gas is best evolved from these solu- 
tions by the addition of from 10 to 30 per cent, of a neu- 
tral salt, preferably calcium chloride or sodium nitrate, 
and heating the mixture in a special boiler. One litre 
of a 40 per cent, solution of formaldehyde gas will evolve 
about 1425 litres (50.1 cubic feet) of the gas at 20° C. 
(68° F.), and will be sufficient for 17 cubic metres (2505.5 
cubic feet) of space. 

u After the disinfection of apartments by formaldehyde 
gas, the latter should be neutralized by ammonia gas, 
evolved from water of ammonia by heat, or by evapora- 
tion from water of ammonia sprinkled upon the floor. 
The quantity of water of ammonia required for neutral- 
ization, after the above-named method, is as follows : 1J 
litres (1.26 quarts) of water of ammonia for each litre 
(1.01 quarts) of formaldehyde solution. 

1 i Disinfection of clothing, bedding, upholstered furni- 
ture, articles of leather, etc., by formaldehyde gas. These 
may be disinfected by formaldehyde gas in the ordinary 
steam disinfecting chamber, the latter to be provided 
with a vacuum apparatus and special apparatus for gen- 
erating and applying the gas. The gas should be ap- 
plied in a dry state in not less than 20 per cent, per 



332 A MANUAL OF HYGIENE AND SANITATION. 






volume strength, the time of exposure to be not less than 
one hour. 

" The application of the disinfectant can, of course, be 
modified to suit the circumstances of the case, but the 
foregoing will be useful as indicating the principles which 
must be followed." 

As to the passengers and others who have been isolated 
in groups, they are to be inspected twice daily by the 
physician and remain under his constant surveillance, 
and can have no communication with any one in a differ- 
ent group or outside of quarantine, except through the 
quarantine officer. The water-supply and food-supply is 
to be strictly guarded, and is issued to each group sepa- 
rately. The latter is to be simple in character and abun- 
dant in quantity, but no fruit is to be permitted. Strict 
cleanliness is to be enjoined, disinfection wherever neces- 
sary, and, in case cholera or other disease appears in 
any group, the sick will be immediately removed to the 
hospital, and the rest of the group bathed and their effects 
disinfected, and all of them removed to other quarters, if 
possible. None are to leave quarantine until five days 
after the last exposure to infection and the final disinfec- 
tion of such effects as were taken to barracks ; and no 
convalescent may leave quarantine until a bacteriological 
examination shows him to be free from infection. 

As has been stated, the treatment of vessels infected by 
other diseases is not necessarily so severe as the above, 
but in each case every effort is made to allow no loophole 
for the entrance of infection into the country ; and in the 
case of yellow fever there is to be the same isolation of 
all not required to care for the vessel and a detention of 
at least five days after disinfection has been thoroughly 
performed and completed. The detention for typhus 



DISINFECTION AND QUARANTINE. 333 

fever is tc be twenty days, and for smallpox fourteen days, 
the detention dating from the last exposure to either dis- 
ease. 

No vessel may leave quarantine until she has a certifi- 
cate from the health (quarantine) officer that she has in 
all respects complied with the quarantine regulations, and 
that, in his opinion, she will not convey quarantinable 
disease. She is then said to be granted free pratique. 

The law further provides that " When practicable, 
alien immigrants arriving at Canadian and Mexican ports, 
destined for the United States, shall be inspected at the 
port of arrival by the United States consular or medical 
officer, and be subjected to the same sanitary restrictions 
as are called for by the rules and regulations governing 
United States ports ; that inspection-cards will be issued 
by the United States officer at the port of arrival to all 
such immigrants, and labels affixed to their baggage, as 
in the case of foreign ports ; and where such immigrants 
are not inspected at the port of arrival they shall enter 
the United States only at certain designated points on the 
frontier, and then only after such inspection, detention, 
disinfection, vaccination, etc., as may be necessary or re- 
quired by the officers there stationed/ ? 

There is also provision for the inspection of State or 
local quarantines from time to time by the Supervising 
Surgeon-General of the Marine Hospital Service, or by 
any officer of that service detailed by him ; and for the 
observance at all quarantines of such additional rules and 
regulations as may from time to time be promulgated by 
him. 

Inland Quarantine. Under this heading may be con- 
sidered the means that may be employed to prevent an 
epidemic extending from one locality or district to an- 



334 A. MANUAL OF HYGIENE AND SANITATION. 

other, although the principle and aims are practically the 
same as those of maritime quarantines, viz., to define 
certain boundaries beyond which no person or thing 
capable of carrying infection may pass, and to establish 
certain points of ingress or egress on these boundaries 
where there may be the necessary detention, inspection, 
disinfection, etc. 

The sanitary cordon " consists of a line of guards, mili- 
tary or civil, thrown around a district or locality, either 
to protect the same from the surrounding country when 
infected, or to protect the surrounding country from the 
infected district or locality. ,? " It is not intended to 
bottle up all the people who are caught within an infected 
district, but, on the contrary, is intended as a means of 
exit to those who will not carry with them contagious dis- 
eases to the people beyond.' n It may be single or double ; 
in the latter case the inner line closely encircles the well- 
defined infected locality, and the outer line the whole sus- 
pected territory. This latter may be removed as soon as 
it is evident that the space between it and the inner line 
is not infected. To be efficient the cordon must be so 
guarded that, even though it be many miles in length, no 
unauthorized person may pass through it, while at certain 
places upon it camps of probation or detention must be 
established, where all persons coming from the infected 
locality may be kept under observation for a time equal 
to the period of incubation of the disease in question. 
These camps of probation or detention are to be distin- 
guished from the camps of refuge, which were first sug- 
gested by Surgeon-General Woodward in 1878, and which 
are " simple residence camps established to receive the 

1 Rone's Hygiene: Quarantine. 



DISINFECTION AND QUARANTINE. 335 

population of an infected community when it has been 
determined to depopulate the infected district." 

At these camps of probation provision must be made 
for inspecting every person and disinfecting all baggage 
before entering camp, for isolating the occupants and 
housing and feeding them in the most comfortable and 
sanitary manner during the detention, for inspections 
twice or thrice daily, for the isolation and care of the sick 
in hospitals at a safe distance from camp, and for the 
issuance of a certificate granting " free pratique " when 
the period of detention is over. 

A notable instance of the sanitary cordon was that about 
the city of Brownsville, Texas, and along the Rio Grande, 
in 1882 ; and of a probation camp, that at Camp Perry, 
Florida, in 1888. 

In addition to these measures it may be necessary or 
advisable to establish a railroad quarantine, as follows : a 
" At certain convenient points, which will be the only 
points of egress by rail from the infected district, an in- 
spection service and disinfecting station are to be main- 
tained throughout the epidemic. Here all the baggage 
and freight are to be properly disinfected and all pas- 
sengers are to be examined by the official inspectors ; if 
the latter are from the infected locality, or have not a 
certificate from some recognized health officer as to where 
they have been for the previous days corresponding to the 
incubative period of the disease, they are to be at once 
remanded to the nearest camp of probation, there to 
undergo the necessary detention. Moreover, it may seem 
advisable to prevent any passenger cars going beyond the 
infected district, and to disinfect all freight and baggage 
cars that do so." 

There may also be local or house quarantines established 



336 A MANUAL OF HYGIENE AND SANITATION. 

by municipal boards of health or other authorities to pre- 
vent not only the family or attendants of the sick from 
mingling with the rest of the community, but to keep 
injudicious outsiders from spreading the infection through 
unwise visitations. And though such isolation may 
appear at times a hardship to certain individuals, and to 
be unduly severe, one should not forget the great cost to 
all concerned of epidemics once inaugurated, nor that it 
is by such stringent measures alone that we shall be able 
to eradicate the infectious maladies from our communities. 

In the foregoing chapter the author is much indebted to Dr. A. C. Abbott's 
Hygiene of Transmissible Diseases for authoritative and up-to date informa- 
tion as to the value of the agents and methods of infection, and the reader is 
referred to this work for an abundance of detail which the limits of the present 
volume do not permit. He has also attempted to present briefly the principles 
and the regulations of quarantine as practised in the United States at the present 
time ; but the reader is referred for further details to the extremely interesting 
and valuable chapter on the subject in Rohe's Text-book of Hygiene, by Dr. 
Wyman, the present Supervising Surgeon-General of the Marine Hospital Service. 



CHAPTEK XI. 

THE REMOVAL AND DISPOSAL OF SEWAGE. 

The waste from dwellings is of three kinds : house- 
sweepings and the ashes from fires ; the waste from 
kitchens, scraps of food, etc., commonly known as garb- 
age ; and sewage, the most important, consisting as it 
does of the solid and liquid excreta of the body, together 
with waste water from wash-tubs, bath-tubs, kitchens, 
laundries, etc. 

Ashes alone have little effect upon the health, except 
that they absorb moisture readily and if allowed to ac- 
cumulate in a cellar may do much to keep it damp and 
mouldy. For the same reason, if they be mixed with 
refuse vegetable matters, putrefaction is favored and 
noxious emanations given off. The dust from ash heaps 
may also be carried into the house and largely increase 
the solid impurities of the air therein. Consequently, 
ashes should be frequently and regularly removed from 
the premises. 

Kitchen garbage readily decays, and if allowed to re- 
main in the vicinity of the house may pollute both the air 
and soil about it ; but inasmuch as it has some value as a 
food for animals, there is usually no difficulty in having 
it removed by scavengers without expense or delay. Care 
must be had, however, that this is done properly and that 
all receptacles are kept in as cleanly a condition as pos- 
sible. Most large cities now find it safer to collect and 

22 



338 A MANUAL OF HYGIENE AND SANITATION. 

cremate the garbage at the expense of the municipality, 
rather than to allow private individuals to keep large 
numbers of animals within or near the city limits for its 
consumption. Even though the former plan be the more 
costly, experience shows that this garbage may be con- 
sumed in properly arranged crematories at convenient 
localities without inconvenience or annoyance to the resi- 
dents of the vicinity, thus saving the expense and time 
necessary for conveying the garbage beyond the munici- 
pal limits. 

The kind of waste to which we give the name sewage 
is, however, of most importance to sanitarians, since it is 
always a possible factor in the production of disease, and 
since it presents the most difficulties in respect to its re- 
moval from dwellings and the ultimate disposal of it. 

In addition to the substances already named and which 
usually come from dwelling-houses, sewage may contain 
the liquid excreta from stables, the refuse from factories of 
all kinds, the drainage from polluted soils, and the excess 
of rain-water not taken up by evaporation or retained in 
the soil. Its composition must, therefore, be always com- 
plex and variable ; but there will be practically always 
present in it chloride of sodium, ammonia, carbon monoxide 
and dioxide, hydrogen and ammonium sulphide, fetid and 
decomposing organic matter, and myriads of bacteria. 
Fresh sewage will not be as offensive to the senses as that 
in which putrefaction has commenced, nor will the gases 
arising from it be as dangerous to health. Frankland 
has shown that " solid or liquid matter is not likely to 
be scattered into the air from the sewage itself by any 
agitation it is likely to undergo until gas begins to be 
generated in it;" and it is really doubtful whether the 
air of a properly constructed and well-ventilated sewer 



THE REMOVAL AND DISPOSAL OF SEWAGE. 339 

can be shown to contain a harmful excess of injurious 
gases and organisms. However, it is essential that sewage 
should always be removed from the premises of a dwelling 
as soon as possible after its production and before decom- 
position begins. 

When the above-mentioned constituents of sewage are 
to be disposed of collectively, the water-carriage system 
is usually the best. Although the pneumatic system 
(wherein air-tight pipes extend from the dwellings, etc., 
to reservoirs from which the air is periodically exhausted 
and the sewage thus drawn into them) would seem to be 
advantageous where the topographical conditions do not 
permit of natural drainage, it is always subject to the 
danger of breaks occurring and destroying the action, 
and seems to have been practically successful in but very 
few instances. 

A modification of the pneumatic system which seems 
to be more successful and practical is the Shone or ejector 
system. In this the sewage is conducted by gravity 
through suitable drains to convenient ejector stations or 
tanks, whence it is forced by means of compressed air to 
the irrigation fields or other places of ultimate disposal. 
The system has been in successful operation in Arad, 
Hungary, since 1896, the plant disposing of the sewage 
of 20,000 persons from five ejector stations at a working 
cost, excluding interest and sinking fund, of about 25s. 
($6.25) per day. 1 

On the other hand, where house refuse only is to be 
considered and where the waste-water can be kept from 
the other parls of the sewage, or where the water-supply, 
the physical conditions, or the cost of constructing the 

1 American Year Book of Medicine for 1900, pp. 549, 550. 



340 -4 MANUAL OF HYGIENE AND SANITATION. 

necessary sewers prevent the use of the water-carriage 
method, recourse must be had to the pail or earth-closet 
system. The use of primitive privy-vaults or cesspools 
is most insanitary and dangerous, and should be con- 
demned in almost every instance. Where the necessity 
for one of the latter seems imperative, it should always 
be made absolutely water-tight, so that none of the con- 
tents may escape to pollute the surrounding soil and 
soil-air or to contaminate the ground-water in the neigh- 
borhood. Moreover, the pits should be properly ventilated 
and should be cleaned out regularly and often, which 
may be done satisfactorily and without offence by some 
form of odorless excavating apparatus, such as is now 
commonly used. 

The daily addition of a solution of chlorinated lime or 
milk of lime or of sulphate of irou, to the extent of about 
two quarts for each person using the cesspool, will do 
much in the way of checking bacterial growth, even 
though it does not actually disinfect the contents, and 
will largely prevent the offensive odors of putrefaction 
from such accumulations. It should be noted that the 
contents of such a vault, or of a simple pit in the earth, 
undergo putrefaction rather than natural decomposition, 
because of the lack of sufficient oxygen supply and of 
the adjunct action of the nitrifying bacteria which are 
found only in the uppermost layers of the soil. 

It is also probable that many disease germs, particularly 
those of diphtheria or typhoid fever, will survive and 
multiply better in the contents of such a vault than in 
sewage or refuse treated by the methods to be hereafter 
described. 

In the pail system the more solid waste matters, and 
especially human excreta, are collected in a suitable pail 



THE REMOVAL AND DISPOSAL OF SEWAGE. 341 

or tab, which, holding only a limited amount, must of 
necessity be removed aud emptied regularly and often. 
If the outbuildings used for this purpose be kept clean 
and properly ventilated, such a system will be both 
economical and healthful. 

Advantage may here be taken of the great deodorizing, 
nitrifying and oxidizing power of fine dry earth, and 
various forms of earth- closets have been devised to be used 
in conjunction with the pail system. If a quantity of dry, 
sifted earth, in bulk about twice that of the dejecta, is 
thrown upon the latter after using the closet, they will 
be rendered inodorous and inoffensive. For this pur- 
pose loam and clay are best, though sifted ashes may be 
used with almost as good results, but sand or gravel will 
not be so efficient as the loam or ashes. Moreover, owing 
probably to the action of the nitrifying bacteria in the 
earth, all trace of the peculiar nature of the organic com- , 
pound is quickly destroyed, and the mixture soon becomes 
practically nothing but humus, and is an excellent fer- 
tilizer. 

The pail- or earth-closet must, of course, be separate 
and apart from the dwelling, as it is impossible to have 
the same means of keeping the gaseous emanations and 
effluvia out of the house as with the water-carriage system ; 
and it also goes without saying, that the liquid house- 
slops, wash-water, etc., must be kept separate from the 
fecal waste, which should be kept as dry as possible to 
lessen putrefaction and to increase its possible value as a 
fertilizer. Nor should this liquid waste be allowed to 
soak into and pollute the soil about the house. It should 
be collected in a water-tight reservoir, whence it can be 
removed at frequent intervals, or, better yet, carried by 
suitable drains to a kitchen garden or other land at a 



342 A MANUAL OF HYGIENE AND SANITATION. 

proper distance from the house, and be there disposed of 
by irrigation or sub-irrigation. 

As one can readily see, this pail system is especially 
well adapted to isolated houses and small communities, 
where each householder can take care that the necessary 
details are properly attended to, and where, as is likely, 
there is not a general water-supply, or where the expense 
of constructing the necessary sewers would be too great. 

But even in cities as large as Manchester, England, 
u where four-fifths of the people are obliged to have 
earth-closets, " the system is said to have proved entirely 
advantageous and practicable. 

Where there is a common and general supply of water 
throughout the house or to a number of houses there must 
be some provision for carrying off the waste- water, and 
as this latter will have probably become polluted in its 
use, it will be advantageous to utilize it to remove the 
other sewage. In fact, where the conditions are favorable 
the water-carriage system will usually be found the best 
of all, because it is more nearly automatic and depends 
least on human interference and efficiency. 

The necessary apparatus comprises, on the one hand, 
that which belongs to the building and its premises, viz., 
the house fixtures, pipes, and drains ; and, on the other, 
the common or public sewers which receive the sewage 
from the house-drains and convey it to its place of ulti- 
mate disposal. 

Sewage-plumbing and House-drainage. 

The essence of any good system for the removal of sew- 
age from a dwelling or building is simplicity. Therefore, 
inasmuch as it has already been stated that sewage should 
always be removed from the premises as soon as possible 



THE REMOVAL AND DISPOSAL OF SEWAGE. 343 

after its production and before fermentation or putrefac- 
tion begins in it, it is evident that in such a system we 
should have for our object and provide for : u 1. The 
speediest possible removal from the house to the public 
sewer of excretal and other refuse by means of water. 2. 
The prevention of the deposit of foul matter in any part 
of the drainage system and of percolation into the soil of 
polluting liquids. 3. The establishment of a current of 
air through every part of the soil-drains and pipes, in 
order to disperse any foul gases that may form and to 
allow them to escape with safety into the open air. 4. 
The prevention of any entry of air from soil-pipes, drains 
and waste-pipes into the house. 5. The exclusion of the 
air of the common sewer from the house-drains and the 
house ; the last being, perhaps, the most important, as 
the air of the public sewer may at any time contain the 
active germs of specific disease." 1 

This is to be done in the manner to be described. The 
soil-pipe is that which receives the sewage from water- 
closets and, usually, from the waste-pipes of other fixtures, 
such as the bath-tubs, washstands, sinks, etc., and which 
connects them with the house-drain; the latter is the 
conduit connecting the soil-pipe with the sewer. Waste- 
pipes convey the contents of washstands and other fixtures 
to the soil-pipes or to a branch of the house-drain. (See 
Fig. 53.) 

The soil-pipe is usually located almost entirely within 
the house, although, were it not for the danger of its con- 
tents freezing, it would be better to have it fastened to 
the wall outside. It is made of cast or wrought iron, 
should be at least four inches in diameter, should convey 
the sewage as directly as possible from the fixtures to the 

1 L. C. Parkes : Hygiene and Public Health, 2d edition, p. 139. 



344 A MANUAL OF HYGIENE AND SANITATION. 

house-drain, and must extend unobstructed from the latter 
to several feet above the roof, ending where winds and 

Fig. 53. 




MAIN SEWER 



Diagram illustrating sewage-plumbing of a house. The traps of the rain-leaders 
at their junctions with the house-drain have been accidentally omitted. 

currents from high walls and chimneys will not interfere 
with its free ventilation. Every branch of the soil-pipe 



THE REMOVAL AND DISPOSAL OF SEWAGE. 345 

more than eight feet in length, or to which two or more 
water-closets are connected, should also .be extended above 
the roof, or else be extended and connected to the main 
soil-pipe above the highest fixture connected therewith, 
as there must be no closed ends wherein foul or stagnant 
air may collect. All joints must be absolutely air-tight, 
and the pipe must be so secured that any vibration or 
settling of the building will not be likely to destroy its 
continuity. In new buildings, especially, all soil-pipes 
should be exposed or else covered in with panels easily 
removable at any time to permit of inspection or repairs. 
Any hidden pipes or those difficult of access should 
be of extra heavy materials, and extra care should be 
given to the joints and supports. The soil-pipe and 
house-drain should both be as smooth as possible interiorly, 
and in the construction they must be carefully inspected 
to prevent any of the material used in caulking or cement- 
ing the joints from projecting within to prevent the free 
flow of sewage. 

Outside of the house the house-drain may be of iron or 
of glazed and impervious earthenware, but no earthen pipe 
should be permitted within five feet of a foundation wall, 
and where any part of the house-drain is within the build- 
ing it should be of iron and securely fastened to the 
foundation- wall above the cellar floor. The connection 
between it and any soil-pipe should be by means of a 
rounded elbow and not by an abrupt right angle. (Fig. 
54.) The house-drain should not be less than four nor 
more than ten inches in diameter, should be laid on a 
firm foundation, should have air-tight joints, and should 
have a slope toward the sewer of at least one-half inch to 
the foot. 

If a house-drain empty into a sewer of the " combined J) 



346 -4 MANUAL OF HYGIENE AND SANITATION. 

system there must be a trap just before its junction with 
the sewer to prevent the passage of sewer-air back into the 

Fig. 54. 




Method of connecting soil-pipe with house-drain. 

house (Fig. 55), and there must also be an opening for fresh 
air between this trap and drain, so that there may be a 

Fig. 55. 




Main trap to be placed between sewer and cesspool, or between house-drain 
and main sewer. (Nottee and Firth.) 



constant current of air through the house-drain and soil- 
pipes to the exit above the roof, and the air in the soil-pipes 



THE REMOVAL AND DISPOSAL OF SEWAGE. 347 

thus kept from becoming foul and stagnant. But if the 
house-drain empties into a sewer of the " separate " system, 
there need be no trap between the drain and sewer, for 
the reasons to be hereafter stated ; however, the fresh-air 
inlet between sewer and house-drain is always advisable, 
as it tends to further assist ventilation. 

A house-drain should not empty into a cesspool, unless 
it is absolutely necessary, and in such case the cesspool 
must be well ventilated and also separated from the drain 
by a fresh-air inlet and trap, just as when the drain 
empties into a combined sewer. Nor should any cess- 
pool empty into a sewer. 

Where rain-water conductors empty into house-drains 
or sewers, they should be separated from the latter by 
traps having a seal of not less than five inches, to prevent 
sewer-air passing up through them to the vicinity of win- 
dows, etc. So, also, all waste and other pipes opening 
into house-drains should be trapped. 

In the house all water-closets and other fixtures should 
be as near the soil-pipe as possible, that there may be no 
long stretches of foul waste-pipe underneath the floors, 
and all connections with the soil-pipe should be made at 
an acute angle, that the discharge into the latter may not 
interfere with its free ventilation. Each fixture must be 
separately trapped and the trap must be located as near its 
fixture as possible. There must be no connection between 
a fixture and the soil-pipe or house-drain which is not 
trapped. 

A little reflection will show that by observing the above 
rules of construction, provision will have been made for 
each of the five specified requirements of the system and 
the air in the soil-pipes will be almost as pure as that of 
the house itself. The absorption of foul gases by the 



348 A MANUAL OF HYGIENE AND SANITATION. 






water in the house-traps and their subsequent dispersion 
into the atmosphere of the house will also be almost 
impossible. Bat there must always be free communi- 
cation between the air inlet into the house-drain and the 
outlets from and at the top of the soil-pipes ; otherwise 
the air in the soil-pipe cannot be changed and foul gases 
will accumulate, which by their pressure would tend to 
force themselves into the house whenever an opportunity 
occurred, and might even overcome the seal of some of 
the traps. 



Fig. 56. 



Fig. 57. 





These illustrations show how a uniform calibre prevents the accumulation of dirt 
in a trap, and how angles and corners favor such accumulations. (Gerhard ) 

Traps are " appliances placed between house conve- 
niences (fixtures) and soil-pipes and drains or sewers, to 
prevent sewer-gas gaining an entrance into the house." 
Most traps are too complicated. The simpler a trap the 
better, provided it have sufficient seal. The seal of a 
trap is the depth of water or the mechanical appliance 
which prevents the back -flow of gas. Mechanical appli- 
ances are liable to become clogged and not to fit tightly, 
thus allowing the passage of sewer-air ; they also tend to 
check the free onward flow of the sewage, thus favoring 
deposition in and preventing the cleansing of the trap. 
The S or siphon trap is as simple as any, is of uniform 



THE REMOVAL AND DISPOSAL OF SEWAGE. 349 



diameter throughout, has no corners or projections to catch 
dirt, and is thoroughly cleansed by each fair flow of water 
through it. The value of a trap does not depend so much 
on the amount of water it contains as on the depth or 
strength of the seal. On account of evaporation the 



Fig. 58. 




S or siphon trap, with opening for ventilation pipe. (Gerhakd.) 

water-seal of a trap soon becomes lessened or destroyed, 
unless the fixture to which it is attached be in frequent 
use ; it is, therefore, advisable to have as few fixtures 
of any kind in the house as the comfort or convenience 



Fig. 59. 



Fig. 60. 





Bell trap. (Gerhard.) 



Cudell's trap. (Gerhard.) 



of the inmates will allow. So, also, if a house is to be 
left unoccupied for a time, it is well to cover the water in 
the traps with oil or glycerin to prevent the evaporation 
of the former. 

The seal of a trap may be broken by siphonage, either 



350 A MANUAL OF HYGIENE AND SANITATION. 

by a heavy rush of water through it from its own fixture, 
or by a rush dowu the soil-pipe from a fixture higher up, 
and this is especially liable to occur if the trap be some 
distance from the soil-pipe, or if the fixtures above dis- 
charge a large amount of water at once. To prevent this 
openings are sometimes made at the top of the traps on 
the side next the waste-pipe or soil-pipe and connected 
with vent-pipes, which should open into the soil-pipe 
above the entrance of the waste-pipe from the highest 



Fig. 61. 



Fig. 62. 





Bower's trap. (Gerhard.) Pot trap (for kitchen sinks, etc.). (Gerhard.) 



fixture, or be continued separately into the out-door air. 
(See Fig. 53.) But this greatly increases the expense, 
and as the vent-pipes, to be efficient, must be almost two 
inches in diameter, they also favor evaporation from the 
trap. If the trap is properly constructed, if the soil-pipe 
is of proper size and height, and if the fixtures be placed 
as near the soil-pipe as possible, there will be but little 
danger of siphonage occurring. Where it does occur, 
McClellan's anti-siphon attachment (Fig. 63) is said to 
work advantageously, being inexpensive and permitting 
a free ingress of air to the trap, but no egress of air from 
the soil-pipe into the house. In this device a small 
weighted and inverted cup rests with its edge immersed 



THE REMOVAL AND DISPOSAL OF SEWAGE. 351 

in a ring of mercury, from which it is raised by the 
atmospheric pressure only when the siphonage sufficiently 
reduces the pressure within the pipes. The mercury and 
the weight of the cup make a seal sufficient to prevent 
any outflow of gas. It is also said that if the waste- 
pipe be connected to the soil-pipe by a divergent opening, 
siphonage will be less likely to occur. 



Fig. 63. 




McClellan's anti-siphon attachment. Sectional view of vent with cup lifted 
out of the mercury by the inflowing current of air, indicated by the arrows. 
(Rohe.) 

All waste-pipes, soil-pipes and house- drains should be 
tested before use by closing all openings and forcing in 
air to a pressure of at least thirty pounds to the square 
inch. Leaks may be detected by plugging the lower 
openings and filling the pipes with water, or by pouring 
an ounce of oil of peppermint into the highest fixture and 
quickly following this with several gallons of hot-water, 



352 A MANUAL OF HYGIENE AND SANITATION. 

the heat volatilizing the oil, whose odor escapes at every 
opening in the pipes unprotected by a trap or water-seal. 










o 
o 

x 

M 

PI 

c 



,0 



O 



The heat imparted by the hot water will also help to trace 
out hidden soil-pipes. 



THE REMOVAL AND DISPOSAL OF SEWAGE. 353 

All fixtures should be exposed to the free ventilation 
of air underneath and about them, and water-closets and 
washstands should not be closed in with carpentry work. 
Traps should also, if possible, be where they may be 
opened and inspected at any time. Under each closed- in 
fixture there should be a drip-safe to catch any leakage 
or overflow of water, but the pipes, if there be any, lead- 
ing from these should never empty into waste-pipes or 
soil-pipps ; they should lead preferably to the open air and 
not to the cellar, as the cellar-air, which is usually impure, 
thus gains access to the house. Even if these drip-safe 
pipes are trapped and open into the soil-pipe, the water 
in the trap is replenished so rarely that evaporation soon 
destroys the seal and allows the air to pass from the soil- 
pipe into the house. 

The overflow pipe of old-fashioned washstands and bath- 
tubs is objectionable, as it collects dirt of all kinds, soap, 
epithelium, etc., and it is almost impossible to clean it. 
Beside, it will often be found opening into the waste-pipe 
below the trap, thus allowing the free passage of sewer-air 
into the room. When new fixtures are being put in they 
should preferably be such as make use of the stand-pipe 
principle in the stoppers and that have no separate or 
concealed overflow-pipe or outlet. 

Water-closets. The requisites for a good water-closet 
are : that it does not allow the escape of sewer-air from 
the soil-pipes into the house ; that it is thoroughly and 
easily cleaned each time after use ; that there are no hidden 
parts in which filth can collect, or which cannot be readily 
cleaned ; that the flushing or washing out of the closet 
be done in such a way that dirt or spray be not thrown 
into the air of the room ; that there be sufficient water- 
supply to wash out the bowl and trap each time and to 

23 



354 A MANUAL OF HYGIENE AND SANITATION. 



refill them to the proper level • that the trap itself is not 
siphoned or left empty by a discharge of water from this 
or another fixture. 

Of the different kinds of water-closets the pan and the 
valve closets are the oldest and the worst, and should not 
be used. They consist of a receiving bowl, the bottom of 
which opens into a swinging pan or is closed by a valve. 
The pan or valve and the lower part of the receiving bowl 
are enclosed in another bowl, the container, connected 



Fig. 65. 



I&bLwjJ&ZAZML 



•■-■•7. r *a 




Pan closet. (Gerhard.) 

with the soil-pipe and trap The depth of water in the 
receiving bowl is regulated by the depth of the pan in pan 
closets, and in valve closets by the location of an overflow 
outlet. In both kinds the contents of the receiving bowl 
are discharged into the container by the tipping of the 
pan or valve, and, consequently, the sides of the con- 
tainer, as well as the under side of the pan or valve, soon 
become thickly coated with filth. This, being hidden, 
accumulates, decomposes and contaminates the air in the 
container, which air is of necessity discharged into the 



THE REMOVAL AND DISPOSAL OF SEWAGE. 355 



room as often as it is displaced by the contents of the 
receiving bowl. In valve closets the overflow-pipe from 



Fig. 66. 




Valve closet. (Gerhard.) 
Fig. 67. 



fig ^S^wpEB^ggS 




S ~-Kfr,- , r-£. 



Plug or plunger closet. (Gerhard.) 



the receiver furnishes an additional way by which the 
foul air may pass from the container into the atmosphere 



356 A MANUAL OF HYGIENE AND SANITATION. 

of the room. It needs no argument to show that these 
closets are decidedly dangerous to health. 

Plug or plunger closets are those in which the outlet 
above the trap is stoppered by a plunger, this being usu- 
ally in a chamber at the side of the receiving bowl. The 
bowl and side chamber holding a considerable quantity of 
water, the trap is well flushed out each time of use ; but 
the side chamber and plunger, being hidden and not easily 
cleaned, soon become coated with filth and dangerous to 
health, as there is nothing to prevent the air from passing 



Fig. 68. 



^^s: 



/^^MMMMMBBg 




Short-hopper closet. (Gerhard.) 

from this chamber into the room. Moreover, the plug 
may not close the opening completely, thus allowing a 
continual waste of water. A trapped overflow-pipe in 
the plunger keeps the closet from overflowing. 

Hopper closets consist simply of a bowl connected below 
with an ordinary trap, and, as there is nothing to get out 
of order, this kind is theoretically one of the best. The 
objection to long hoppers is that dirt is apt to stick to the 
sides and become offensive, but this can be prevented if it 
is so arranged that water begins to flow down the sides as 
soon as the closet is put to use, thus preventing adhesion. 



THE REMOVAL AND DISPOSAL OF SEWAGE. 357 

Short hoppers have not this objection, as the feces fall 
directly into the water in the bowl and are carried out 
through the trap as the bowl is flushed. All water-closets 
should have a flushing rim encircling the top, so that all 
sides of the bowl may be washed down and cleansed each 
time the closet is used. 

Wash-out closets retain considerable water in the bowl, 
and are emptied by a strong flash of water from the flush- 
ing rim. They are simple, do not readily get out of order, 
and are much in favor at the present time. As they are 
a modification of the short-hopper closet, so is the siphon 
closet a modification of the wash-out. 



Fig. 69. 




Wash-out water-closet. (Parkes.) 

In the siphon closet the contents of the bowl and trap 
are lifted out by siphonic action, and then the bowl and 
trap are refilled, as in the case of wash-out closets, by an 
after flush. In the Dececo closet — a siphon closet — use 
is made of the principle involved in the Field flash tank. 
Hopper, wash-out and siphon closets should be supplied 
from water-closet cisterns, which should give down a cer- 
tain and sufficient volume of water with only a short pull 
on the chain. The bowl and trap should also be auto- 
matically refilled from the cistern after use. 

Water-closets should not be connected directly to the 






358 A MANUAL OF HYGIENE AND SANITATION. 



water-supply pipes of the house, as air from the closets 
may be sucked into them at times when the water-supply 






Fig. 70. 




■ 



Dececo siphon closet. (Paekes.) 

is cut off, and the water afterward contaminated by it. 
But this is hard to avoid in pan, valve or plug closets, 
and is another serious objection to their use. 

Vent-pipes from the bowl and seat of water-closets 
must be large, and must not open into the soil-pipe but 

Fig. 71. 




Automatic injector for disinfecting traps, water-closets, etc. 



into the open-air ; they must not open near a window nor 
any place from which air is taken into the house, but may 






THE REMOVAL AND DISPOSAL OF SEWAGE. 359 

open into a flue which is constantly heated, as a kitchen 
chimney, or may themselves be heated and have a current 
maintained in them by a small lamp or gas-jet. In this 
way the room in which a water-closet is located may be 
effectively ventilated. 

Water-closets should never be placed in dark closets, 
nor in bedrooms or living-rooms, but should always be 
in separate rooms that have free communication with the 
open air by means of a large window or by a ventilating 
shaft of at least four square feet sectional area through- 
out its entire length. It is also advisable that bedrooms 
should not communicate directly with bath-rooms, etc., 
containing water-closets, unless there is every assurance 
that the closet and plumbing connected with it are first- 
class in every particular. 

A recent device which is intended for attachment to the 
flush-pipes of water-closets and to the waste-pipes of other 
fixtures between them and their traps, automatically dis- 
charges with each flow of water through the respective 
pipes a sufficient quantity of an antiseptic to prevent all 
growth of micro-organisms in the traps or their contents. 
(Fig. 71.) This, when used, aids not only in obviating 
the escape of harmful or disagreeable gases into the house, 
but will largely prevent the addition of disease germs to 
the contents of the public sewer. 

Sewers. These are the conduits provided to receive 
and convey the contents of house-drains and other drains 
to the place of final disposal or discharge. They may be 
of either of two kinds — "combined" or "separate" 
Sewers of the former class, which have heretofore been 
most commonly used in this country, are constructed to 
carry off all kinds of sewage, the waste liquids, etc., from 
factories, street washings, and the surplus rain-water of 



360 A MANUAL OF HYGIENE AND SANITATION. 






the district drained by them. As this necessitates a size 
and capacity sufficient to receive the greatest probable 
rainfall upon the area drained in addition to the other 
sewage, it is evident that the depth of the usual daily volume 
of the latter in the sewer will be so shallow and the cur- 
rent so sluggish as greatly to favor the settling of the solid 



Fig. 72. 




Section of ovoid sewer of " combined " system. 

and semi-solid constituents, the obstruction of the sewers, 
and the development of bacteria and sewer-gas. To obvi- 
ate this and to ensure a more rapid flow by keeping the 
depth of sewage as great as possible, the smaller conduits, 
at least, are generally made ovoid in section, the smaller 
end, of course, being downward. " Combined" sewers 



THE REMOVAL AND DISPOSAL OF SEWAGE. 361 

are not only more expensive to construct and to keep in 
repair than those of the separate system, but greater care 
must be had to see that they are at all times properly 
ventilated. The main advantage claimed for them is that 
the expense of constructing separate conduits for factory 
wastes, street washings and the excess of rain-water is 
avoided ; but this is a doubtful one, both in respect to 
economy and sanitation. 

The ventilation of sewers of this kind is usually suffi- 
ciently provided for by the inlets for street washings and 
rain-water, located at street-corners, etc. ; but if these 
are not close enough together to keep the sewer atmosphere 
constantly changing and reasonably pure, other ventila- 
tion openings should be made. But in all cases the air 
from sewers of the combined system must be excluded 
from house-drains, etc., by the traps which have already 
been described. 

To the sewers of the u separate " system only the sew- 
age proper from dwellings and, occasionally, from small 
factories, is admitted, the rain-waters, surface-waters and 
soil- waters being removed by other drains or chanuels. The 
advantages of this system, which is now indorsed by almost 
all sanitarians, are that the volume of sewage to be carried 
is comparatively small and constant, and that it can be 
calculated very approximately from the daily water-supply 
and population ; that the cost of construction is much less 
than that of sewers of the combined system, and that, 
while it is perfectly available and satisfactory for large 
cities, it is the only one that small communities would 
consider or can afford ; that the sewage is more concen- 
trated and uniform in composition, and can thus be better 
utilized as a fertilizer or disposed of in whatever manner 
may be desirable ; that the sewers, having smaller and 



362 A MANUAL OF HYGIENE AND SANITATION. 






smoother walls, are more frequently and effectually flushed, 
and that they are more completely ventilated and alto- 
gether better suited to the work to be performed. The 
disadvantages of sewers of this class are that a community 
must have two sets of drains, one for sewage and the other 
for rain, street and factory waters, and that after a long 
dry season the street washings, etc., may be very foul ; 
but these are outweighed by the advantages above men- 
tioned. 



Fig. 73. 



r — *\ 
Id 



^r 




Field's annular siphon flush-tank. (Parkes.) 



" No sewer of this system should be more than six 
inches in diameter until it and its branches have accumu- 
lated a sufficient flow at the hour of greatest use to fill 
this size half-full, because the use of a larger size is waste- 
ful and because ventilation becomes less complete as the 
size increases. The size should be increased gradually 
and only so rapidly as is necessary by the filling of the 
sewer half-full at the hour of greatest flow ; and the upper 
end of each branch sewer should be provided with an 
automatic flush-tank of sufficient capacity to secure the 
thorough daily cleansing of so much of the conduit as 



THE REMOVAL AND DISPOSAL OF SEWAGE. 363 

from the limited flow is liable to deposit solid matters by 
the way." 

There should ordinarily be no traps between house-drains 
and sewers of the separate system, since, having no rain- 
water inlets, the latter would otherwise have no openings 
for ventilation. Moreover, since the il separate 7 ' sewers 
are so regularly and thoroughly flushed, the air in them is 
not likely to be so impure, and there is not the same reason 
for excluding it from the house-drains, etc., as there is 
regarding the air from " combined ?; sewers. The junc- 
tions of house-drains with sewers of the separate system 
should be by divergent openings, so that the air may pass 
freely into the drain as the sewage empties into the sewer. 

Should one desire, however, to separate his house-drain 
from the public sewer by means of a trap, and thus pre- 
vent the ingress of sewer-air into his premises, the venti- 
lation of the sewer can be secured by providing a vent-pipe 
between the trap and the sewer. But in no case must the 
inlet-pipe on the other side of the trap, between it and 
the house, be omitted ; nor should the two air-pipes be so 
near together that air from the former will be likely to 
be drawn into the latter. 

All sewers should be laid on a good foundation with 
sufficient fall to give at least a velocity of two feet per 
second to the flow. If made of bricks they should be 
laid in a mortar made of cement and sharp sand, and all 
sewers should be as smooth as possible inside to prevent 
the arrest of particles of sewage. Sewers of the com- 
bined system should not be pervious to the soil-water, as 
the liquid sewage is just as apt to pass from them to the 
soil and to pollute it dangerously as the soil-water is to 
pass into the sewers. But the rain-water drains of the 
separate system may also be employed to drain the subsoil. 



364 A MANUAL OF HYGIENE AND SANITATION. 



\ 



The ultimate disposal of sewage is a matter of con- 
siderable importance which commonly does not receive 
the attention it deserves. The usual method in this coun- 
try of discharging the sewage into a running stream is 
reprehensible, because the natural purification of a water 
thus contaminated must always be slow and more or less 
uncertain, and because the risk to those using the pol- 
luted water must be a constantly increasing one. Where 
the district drained and supplied by the stream is a sparsely 
settled one, and where the volume of fresh or running 
water is very large in proportion to the quantity of pol- 
lution it receives, the objections to the disposal of sewage 
in this way may be theoretical rather than practical ; but 
as the population increases and the ratio of pure water to 
filth decreases beyond certain limits, the question becomes 
more serious and pertinent. It is said that to safely 
dilute the sewage of 1000 persons requires from two to 
four million gallons of unpolluted water per day, this, of 
course, not destroying the disease germs nor eliminating 
the danger of their multiplication. 

Other methods of sewage disposal resemble closely 
those already described for the purification of water, in 
that they make use of subsidence, chemical treatment, 
and filtration. The sewage may be collected in large 
tanks, with or without the addition of certain chemicals, 
such as lime, alum or sulphate of iron, to increase the 
precipitation, and the suspended impurities allowed to 
settle to the bottom of the tanks, whence they can be 
removed, squeezed partially dry in hydraulic presses 
and either disposed of as a fertilizer or cremated. The 
clear effluent or liquid part of the sewage may be allowed 
to flow at once from the settling tanks into a convenient 
watercourse, provided it is there well diluted, or it may 



THE REMOVAL AND DISPOSAL OF SEWAGE. 365 

better be filtered through an area of porous soil or through 
prepared filter-beds. If the filtration is properly done the 
filtrate will contain nothing harmful, and may be allowed 
to flow where it will without danger. A properly pre- 
pared filter-bed of twelve inches of sand upon eighteen 
inches of gravel or magnetic carbide of iron, with an area 
of one acre, is said to be able to purify from one to two 
million gallons of clarified — effluent — sewage in twenty- 
four hours. 

Chemical treatment will probably cost from thirty-five 
to fifty cents or more per annum per individual of the 
population supplying the sewage, but an even more im- 
portant question than cost is as to whether the addition 
of the chemicals may not interfere with the natural biologic 
processes of purification constantly taking place in most 
sewage. Chemicals that are or have been used as pre- 
cipitants are lime, lime with alum, sulphate of iron or 
alkali waste, sulphate of iron alone, and a combination of 
alum, charcoal and clay. The precipitate obtained with 
the latter make a superior .fertilizer. 

Sewage may also be disposed of by intermittent down- 
ward filtration, either through specially constructed filter- 
beds or a prepared area of soil; by irrigation or sub- 
irrigation, and by the so-called septic-tank method. 

For sewage, intermittent filtration is superior to the 
continuous process ; in fact, is almost essential, as the 
interruption in the percolation permits a renewal of the air- 
supply in the filtering medium or soil, and thus furnishes 
a sufficient quota of oxygen for the alteration and oxida- 
tion of the excessive amount of organic matter in the sew- 
age. With sufficiently frequent intermittence, fine sand, 
such as is used for building purposes, makes an excellent 
artificial filter, capable, it is stated, of purifying 50,000 



366 ^ MANUAL OF HYGIENE AND SANITATION. 

gallons of crude sewage per acre per day and of removing 
all the solids, much of the dissolved matters and 99 per 
cent, of the contained bacteria. Where the crude sewage 
is allowed to settle or is treated biologically in the septic 
tanks, a much greater quantity of the clarified effluent 
can be filtered daily, as is indicated above. 

By intermittent soil filtration we mean " the concentra- 
tion of sewage at short intervals, on an area of specially 
chosen porous ground, as small as will absorb and cleanse 
it ; not excluding vegetation, but making the produce of 
secondary importance. The intermittency of application 
is a sine qua non even in suitably constituted soils, wher- 
ever complete success is aimed at." l The land should be 
levelled and underd rained with tile drains at the depth of 
five or six feet, and should be divided into four parts, no 
part to receive sewage for more than six hours. An acre 
of properly prepared soil will thus dispose of the crude 
sewage of 1000 to 2000, or the clarified sewage of 5000 
people. 

The soil to be used for this purpose, as well as that for 
irrigation and sub-irrigation, should be porous and loamy; 
if clay, it should be well broken up and mixed with ashes ; 
sand does not do well, especially at first in these methods. 
The sewage impurities are removed partly by mechanical 
filtration, but especially by oxidation, the latter being due 
partly to the air in the interstices of the soil, but chiefly 
to the saprophytic bacteria, which rapidly convert the 
organic impurities into nitrates and nitrites. 

Irrigation means " the distribution of sewage over a 
large surface of ordinary agricultural ground, having in 
view a maximum growth of vegetation, consistently with 

1 Metropolitan Sewage Commission : See Notter and Firth, p. 546. 



THE REMOVAL AND DISPOSAL OF SEWAGE. 367 

due purification, for the amount of sewage supplied. 5 n 
Sub-irrigation is a modification of this, the sewage being 
delivered through porous drains a few inches beneath the 
surface of the soil. Unless very porous, the land should 
be underdrained ; it should also be levelled to prevent 
the sewage flowing off the surface too rapidly. The un- 
derdrains need not be nearly so close together, however, 
as in the intermittent filtration system. The crops raised 
on irrigation farms are perfectly healthful in every re- 
spect, and there can be no reasonable objection to their 
use ; there would be decided objection, however, to 
watering the vegetables with sewage water. 

On the large irrigation farms of the city of Berlin, the 
cost of sewage precipitation is about covered by the returns 
from the crops raised upon them. The mortality of 
those employed upon them is very low, and there seems 
to be no particular tendency to illness that can be at- 
tributed to the sewage. It is even said that the employes 
use with impunity the clear water in the effluent canals 
for drinking and other purposes. Paris has also adopted 
the irrigation method, and it is expected that by the end of 
the present year (1900) the sewage of the entire city will 
be treated in this way. The sewage of from one hundred 
to one hundred and fifty persons per acre may be satis- 
factorily disposed of by irrigation, Berlin's rate, with an 
especially favorable soil, being one hundred and forty- 
two per acre. It is to be especially recommended for 
isolated houses, for small communities or for charitable 
or other State institutions. 

The " septic-tank " system for the disposal of sewage 
particularly aims to take advantage of the biologic and 

1 Metropolitan Sewage Commission : See Notter and Firth, p. 547. 



368 A MANUAL OF HYGIENE AND SANITATION. 

saprophytic action occurring naturally in all polluted 
waters. The idea is to favor and not to hinder the purify- 
ing bacteria and other agencies by placing the sewage 
under the conditions most favorable to their growth and 
action, thus facilitating the conversion of organic matters, 
both solid and dissolved, into substances entirely harmless 
and unobjectionable. " As compared with the process 
of chemic precipitation and sedimentation, the bacterial 
process presents the following advantages : (a) It requires 
no chemicals, (b) It produces no offensive sludge, but 
only a deposit of sand or vegetable tissue which is free 
from odor, (c) It removes the whole of the suspended 
matter, instead of only about 80 per cent, thereof, (d) It 
effects the removal of 51.3 per cent, of the dissolved 
oxidizable and putrescible matter, as compared with the 
removal of only 17 per cent, effected by the present 
chemical treatment, (e) The resultant liquid is entirely 
free from objectionable smell, and does not become foul 
when it is kept ; it further maintains the life of fish." * 

Electricity has also been suggested as an agency for the 
purification of sewage, but seems to be still too expensive 
for the purpose. In the Webster process iron electrodes 
are used, and the good results are supposed to be due 
partly to the hypochlorites which are formed from the 
chlorides always present in the sewage, and partly to the 
carbonates and oxides of iron which not only deodorize 
but help to rapidly oxidize the organic matters. By 
this method about 70 per cent, of the putrescible matters 
and almost all the bacteria are removed from the sewage, 
but it is quite costly yet on account of the large amount 
of iron consumed. 

1 American Year Book of Medicine for 1900, page 549. 



CHAPTEE XII. 

MILITARY HYGIENE. 

This subject is one which has to do with active and 
presumably healthy men under conditions more or less 
abnormal and sometimes of peculiar and unusual stress. 
Moreover, the actual financial value of the life and health 
of the individual to the State is more directly manifest 
than under ordinary circumstances, and, though at times 
the interests of the former must be sacrificed to those of 
the latter, it is of the highest economic and practical im- 
portance that a government should conserve as far as 
possible the health and welfare of each member of its 
army and navy. Consequently, much thought should be 
and is given to all those questions which rightly come 
under this head, and the effect of the efforts made in this 
direction is very decided, especially with reference to the 
regular or standing armed force of the country. 

Men who have become accustomed to military ser- 
vice, and to whom it is a real and permanent business, 
have probably a better health status than the average 
citizen, owing to the regularity of their habits and work 
and to the oversight and care which are given to the details 
of their life. Conditions are much different, however, 
when men are suddenly called from many occupations 
and ways of living to volunteer or militia service. They 
do not accommodate themselves readily to the change, nor 
do they appreciate the importance of details that may 

24 



370 A MANUAL OF HYGIENE AND SANITATION. 

seem trivial to thern but that have great bearing on their 
future health Often the utmost efforts on the part of 
those in authority and who are skilled in these matters 
are apparently of no avail and lead to undeserved censure. 
How much more serious actual neglect of hygienic meas- 
ures may be has been proven more than once in the past. 

The following quotation from the Report of the Sur- 
geon-General of the Army for 1899 is pertinent : 

" Hygiene is one of the principal subjects of examina- 
tion for candidates desiring appointment in the medical 
corps of the army, and at the subsequent examinations 
for promotions to the grades of captain and major it is 
given a most prominent place. It is also the most promi- 
nent subject in the course of instruction at the Army 
Medical School, where the student officers spend five 
hours daily for a period of five months in practical labora- 
tory work relating for the most part to the cause and pre- 
vention of infectious diseases ; but the comparatively 
small number of medical officers of the regular army 
available for duty in the large camps occupied by our 
volunteer troops at the outset of the war (Spanish-Ameri- 
can) proved to be entirely inadequate to control the sani- 
tary situation in these camps." 

In a study of military hygiene, all phases of the routine 
life of the soldier should be discussed, for it is the combi- 
nation of these that make for good or evil. 

Unless the emergency is grave and large numbers of 
men are needed quickly, much attention should be paid 
to the selection of the men, and only those enlisted who 
satisfy certain physical requirements. They should be 
neither abnormally short nor tall; the weight should be 
in proper ratio to the height; the vision and general health 
good ; and especially should the chest measurement and 



MILITA R Y HYGIENE. 371 

expansion or u vital capacity" be considered as of great 
importance. 

"It has also been observed that a close correlation 
exists between the physical and moral development of 
men; in fact, lowering the physical means lowering the 
moral standard of recruits." 1 

Age is also a factor that should be considered. If 
recruits are too young, they are not able to withstand 
long-continued work or strain, nor will they be so likely 
to resist the incurrence of disease. On the other hand, 
men who are too old will be more liable to have habits of 
life or taints of chronic disease that will interfere with 
their military duty, and they will also not serve the 
maximum length of time that makes their work most 
economical to the government. 

In selecting the sites for camps or homes of soldiers, 
consideration must be had as to whether these are to be 
temporary or permanent, and as to whether the men are 
to live in tents or barracks. In any case, there should be 
sufficient space allotted to each command; there should be 
no interference with the free circulation of air, and the 
soil should be dry, porous and readily drained. The 
ground- water especially should not be too near the sur- 
face. Camps should not be located, except in event of 
grave military necessity, on ground that has been recently 
occupied by other troops; nor should they be on clay 
soils, in ravines or valleys where they will receive the 
drainage from higher ground or other camps, nor near 
marshes or the marshy banks of rivers, nor where they 
will receive the winds from malarial districts. Thought 
should also be given to the source and abundance of the 

' N otter and Firth, p. 917. 



372 A MANUAL OF HYGIENE AND SANITATION. 

water-supply and its relation to the natural course of 
drainage from the camp. 

If tents are to be used, these must be such as to afford 
both thorough protection and good ventilation. They 
should not be too crowded, either as regards the number 
of occupants or the location of the tents one to another. 
If the camp is of extended duration, the tents should be 
floored, or, at least, the men should not sleep on the 
ground. 

A trench should also be dug about each tent to prevent 
flooding by rains, and from time to time the tents should 
be moved about, as "it is well-known that tents occupy- 
ing the same ground for a length of time become un- 
healthy." Camp kitchens, stables, sinks, latrines, etc., 
should be as far from the sleeping tents as reasonable con- 
venience permits, and to the leeward of prevailing winds. 
All camps should be regularly and carefully policed, and 
" the fact that a camp expects to change its position does 
not justify neglect of proper policing of the ground oc- 
cupied." 

In the regulations and instructions issued in 1895 by 
the British Quartermaster-Genera? s Department the fol- 
lowing points are laid down as of importance : 

" 1. The length of time troops are to occupy the camp- 
ing-ground. 2. That order, cleanliness, ventilation and 
salubrity are to be ensured. 3. That means of passing 
freely through the camp are essential. 4. That a strag- 
gling camp increases labor of fatigue duties, and impedes 
delivery of supplies and circulation of orders. 5. That 
the more compact the camp, the easier it is to defend." x 

If the soldiers are assigned to forts or other permanent 
encampments, they will probably be quartered in barracks, 

i Notter and Firth, p. 936. 



MILITARY HYGIENE. 373 

and these will have been constructed according to specifi- 
cations. However, it should be remembered that in these 
attention must be given not only to the comfort of the 
men, but to their sanitary needs as well, and that the 
chief faults in such structures in the past have been in- 
sufficient ventilation and improper location and arrange- 
ment of toilet rooms, etc. 

Barrack buildings should not be over two stories in 
height, should be comparatively narrow, should have free 
ventilation and access of sunlight about them, and should 
be so placed that they do not interfere with one another 
in these respects. It will be well if each sleeping-room 
is planned to contain not more than twenty-five men or 
a quarter company. Each man should have at least 600 
cubic feet of air-space in his dormitory ; with ceilings 
twelve feet high, this will give him fifty square feet of 
floor space. Toilet-rooms should be separated from th6 
dormitories by a continually ventilated passage-way, at 
least ; it would be better to have the former entirely apart 
from the latter. 

Kitchens, dining- or mess-rooms, guard-rooms and 
quarters for married men should be in separate build- 
ings and apart from the barracks, and these should each 
be properly arranged for its purpose. The same remarks 
apply to the post-hospital, which should have as complete 
an equipment as possible in accordance with the demands 
of modern medical and surgical science; and, consequently, 
in addition to the general wards, there should be others 
for the isolation of contagious or infectious cases and for 
the insane. It goes without saying that the officers' quar- 
ters should have every hygienic and sanitary advantage 
and convenience, both as to construction and location, 
that the circumstances of the post will permit. 



374 A MANUAL OF HYGIENE AND SANITATION. 

In such permanent encampments, where the accommo- 
dations and conveniences more nearly resemble those in 
the home of the average private citizen, and where proper 
food, an ample supply of unpolluted water and suitable 
arrangements for the removal of wastes and sewage can all 
be provided for, it will ordinarily not be difficult for the 
well-informed medical officer to maintain a satisfactory 
sanitary condition, and, owing to the discipline and super- 
vision of their habits to which the men are subjected as 
well as to the fact that they are adults and males, the 
general health status of the post should usually be better 
than the average of the neighboring communities. 

But conditions and circumstances are much different on 
the " tented field," and especially so if the command 
belong to the militia or volunteer service, in which the 
men have been called from many and various occupations, 
are unaccustomed to the hardships of military life and 
the vicissitudes of out-door living, and are unmindful — 
as they will be at first — of the restraints and value of dis- 
cipline. Even though the medical officers be well versed 
in hygienic knowledge and thoroughly aware of the im- 
portance of the strict observance of sanitary precautions, 
and though they have the hearty assistance of the com- 
manding officers, it will take much time to so instruct the 
men that they will not endanger the health of themselves 
and others, and eternal vigilance and much effort will be 
the price of a continuously satisfactory state of affairs. 

The recent experience of this country in the Spanish- 
American war is vivid in the minds of every one, espe- 
cially as regards the sanitary conditions and the epidemic 
sickness in practically all the camps throughout the coun- 
try. And while there was much that was censurable, 
there was still much unjust censure given by those who 



MILITARY HYGIENE. 375 

did not understand to those who did and who strove to 
the utmost to overcome the untoward and unfortunate 
conditions. 

In August, 1898, a board of medical officers was ap- 
pointed by the Surgeon-General of the United States 
Army to " ascertain the causes of the existence and spread 
of typhoid fever in the national encampments, and to 
suggest means of its abatement." The results of their 
work, as epitomized by one of them, Prof. Victor C. 
Vaughan, in his u Oration on State Medicine" before the 
annual meeting (1900) of the American Medical Associa- 
tion, 1 are very instructive and are worth quoting almost 
entire. 

" Every regiment iu the United States service in 1898 
developed typhoid fever. Typhoid fever not only ap- 
peared in every regiment in the service, but it became 
epidemic, both in the small encampments of not more than 
one regiment, and in the larger ones consisting of one or 
more corps. Typhoid fever became epidemic in camps 
located in the Northern as well as those in the Southern 
States; and it is so widely distributed in this country that 
one or more cases are likely to appear in any regiment 
within eight weeks after assembly. Typhoid fever usually 
appears in military expeditions within eight weeks after 
assembly. 

" With typhoid fever as widely disseminated as it is in 
this country, the chances are that if a regiment of 1300 
men should be assembled in any section and kept in a 
camp, the sanitary conditions of which were perfect, one 
or more cases of typhoid fever would develop. 

" Neither the miasmatic theory nor the pythogenic 
theory of the origin of typhoid fever is supported by the 

1 See Journal of American Medical Association, June 9, 1900. 



376 A MANUAL OF HYGIENE AND SANITATION. 

investigations, but they confirm the doctrine of the specific 
origin of typhoid fever. It is disseminated by the trans- 
ference of the excretions of an infected individual to the 
alimentary canals of others, and it is more likely to be- 
come epidemic in camps than in civil life, because of the 
greater difficulty of disposing of the excretions from the 
human body. A man infected with typhoid fever may 
scatter the infection in every latrine of a regiment before 
the disease is recognized in himself. 

" Camp pollution was the greatest sanitary sin com- 
mitted by the troops in 1898, and it may be stated in a 
general way that the number of cases of typhoid fever in 
the different camps varied with the method of disposing 
of excretions. The tub system of disposal of fecal matter 
as practised in certain divisions is to be condemned, and 
the regulation pit system is not a satisfactory system of 
disposing of fecal matter in permanent camps. The 
board has recommended that in permanent camps where 
water-carriage cannot be secured, all fecal matter should 
be disinfected and then carted away from camp. 

"Some commands were unwisely located, and in some 
instances the space allotted the regiments was inadequate. 
Many commands were allowed to remain on one site too 
long, and requests for change in location made by medical 
officers were not always granted. Greater authority 
should be given medical officers in matters relating to the 
hygiene of camps. Superior line officers cannot be held 
altogether blameless for the insanitary condition of the 
camps. 

"Infected water was not an important factor in the 
spread of typhoid fever in the national encampments in 
1898. Flies undoubtedly served as carriers of the infection ; 
it is probable that the infection was disseminated to some 



MILITARY HYGIENE. 377 

extent through air in the form of dust ; personal contact 
was undoubtedly one of the means by which it was spread, 
and it is more than likely that men transported infected 
material on their persons and clothing, and thus dissemi- 
nated the disease. 

"A command badly infected with typhoid fever does not 
lose the infection by simply changing location, but when 
it changes its location it carries the specific agents of the 
disease in the bodies of the men, in their clothing, bed- 
ding and tentage, and even an ocean voyage does not 
relieve an infected command of its infection. However, 
after a command becomes badly infected with typhoid, 
change of location, together with thorough disinfection of 
clothing, bedding and tentage, is necessary. 

" Except in case of most urgent military necessity, one 
command should not be located on a site recently vacated 
by another, but the fact that a command expects to change 
its location does not justify neglect of proper policing of 
the ground occupied. 

" It is desirable that soldiers' beds should be raised from 
the ground, and medical officers should insist that soldiers 
remove their outer clothing at night when the exigencies 
of the situation permit. In some of the encampments 
the tents were too much crowded. 

"Malaria was not a prevalent disease among the troops 
that remained in the United States, and while the inves- 
tigations show that coincident infection with malaria and 
typhoid fever may occur, the resulting complex of symp- 
toms does not seem to be sufficiently well defined and 
uniform to be recognized as a separate disease. The con- 
tinued fever that prevailed among the soldiers in this 
country in 1898 was typhoid fever, but in military prac- 
tice typhoid is often apparently an intermittent disease. 



378 A MANUAL OF HYGIENE AND SANITATION. 

"About one-fifth of the soldiers in the national encamp- 
ments in the United States in 1898 developed typhoid 
fever; army surgeons correctly diagnosed a little less than 
one-half the cases of typhoid fever, and while the deaths 
from typhoid fever were more than 80 per cent, of the 
total deaths, the percentage of deaths among cases of 
typhoid fever was about 7.5. When a command is thor- 
oughly saturated with typhoid it is probable that from 
one-third to one-quarter of the men will be found suscep- 
tible to the disease. 

" The belief that errors in diet, with consequent gastric 
and intestinal catarrh, induced typhoid fever, or that 
simple gastro-intestinal disturbances predispose to it, is 
not supported by the investigations. More than 80 per 
cent, of the men who developed typhoid fever had no 
preceding intestinal disorder. 

" The shortest period of incubation in typhoid fever is 
probably something under eight days, and one who has 
lived in a camp in which typhoid fever is prevalent is 
liable to develop this disease any time within eight weeks 
after leaving such a camp." 

So much has been included in the above quotations, 
looking in so many different directions, that it would 
seem that there were little more to say on the subject. 
However, a few words must be added. 

Despite the fact that malaria was apparently not very 
prevalent among the troops in this country in the late 
war, it is a disease that is often very harmful and disas- 
trous to armies. So is dysentery and, in other climates 
or countries, yellow fever and cholera. On account of 
the recent discoveries regarding the influence of the mos- 
quito in causing malaria, a simple mosquito bar or net 
should be included in the kit of every soldier, and the 






MILITARY HYGIENE. 379 

Surgeon-General's report of 1899 seems to give evidence 
already of its efficacy in preventing the disease among 
our soldiers in Cuba. As dysentery and cholera are well 
known to be transmitted by the drinking-water, and yel- 
low fever often by fruit, sanitary precautions as to the 
care of each of these must be observed. Though the 
quotation above states that " infected water was not an 
important factor in the spread of typhoid fever, etc.," it 
must not be inferred that no cases were found to be due 
to such water. In fact, many cases were undoubtedly 
thus caused, as Dr. Vaughan clearly states; but the 
authorities, early realizing the dangers that might be due 
to a bad water, made such efforts to obtain pure supplies 
that other means of infection became relatively more 
important. Every effort should therefore be made to 
secure the purest water-supply possible in every military 
camp, and to have it thoroughly sterilized before use if 
there is any suspicion of its pollution. A full description 
of filtration methods and of the sterilizer that has been 
adopted by the army has already been given in the chapter 
on Water. 

As the efficiency of the soldier depends so much upon 
his food and as it is of importance for so many different 
reasons, it is not strange that it has been the subject of the 
most careful investigation. In fact, much of the scien- 
tific knowledge now pertaining to dietetics is the result of 
the work of the various governments in their efforts to de- 
termine the most satisfactory and efficient military rations. 
Considering the men simply as machines, true economy 
requires that their food shall be ample in quantity and 
good in quality. Attention must also be given to its 
transportation and preparation, and to its character as a 
source of heat and energy. 



380 -4 MANUAL OF HYGIENE AND SANITATION. 



I 



A study of the standard daily rations of the various 
armies of the world at once shows a noticeable uniformity 
amoug them in the amounts and relative proportion of 
the food principles and in the ratio of nitrogen to carbon. 
And as these have all had the test of long time and hard 
experience, they serve to establish their own scientific 
accuracy, as well as that of the dietetic ratios which 
have been determined in other ways and to which they 
so closely correspond. 

No part of a military administration is of more impor- 
tance than the commissary department, for an army with- 
out food is soon worse thau useless. But it is not easy to 
properly feed large numbers of men in an active campaign 
when the whole body is moving rapidly from place to 
place and when the exigencies of the day may seem to 
require all available means of transportation for other 
purposes. Consequently, much effort has been made to 
supply rations that are condensed in bulk and that require 
as little immediate preparatiqn as possible. 

Considerable advance in this line has been made in 
recent years, and various soups, meats and vegetables, 
condensed and ready-cooked, are now often supplied when 
the same cannot be had in a fresh state. That such may 
be entirely satisfactory cannot be denied, but those in 
authority must be especially careful as to certain points, 
viz., that the food is not lacking in quality and that the 
processes employed have not impaired its dietetic value or 
digestibility nor permitted harmful changes to take place 
in it. The temptations of the army contractor are often 
hard to withstand ; moreover, tests have shown that if 
concentration be carried too far, not only the digestibility 
but the nutritive value of th'e food may be seriously im- 
paired. Thus the valuable salts may be lost with the 



MILITARY HYGIENE. 381 

water in the compression of vegetables. Again, the pro- 
cesses may make the foods too uniform in taste, or there 
may he the omission of such accessories as vinegar, spices, 
etc., or there may be ignorance as to how to cook them 
properly ; and it must always be remembered that pala- 
tability has much to do with digestibility. For these 
reasons it will be wise to have at least part of the food 
issued in as nearly the fresh or ordinary state as possible. 

Space does not permit consideration of the various 
articles of food composing the prescribed ration, but it is 
evident that the laws of dietetics govern here as else- 
where. It may be well to say, however, that experience 
seems to show that alcohol should not be included in the 
regular ration, but should only be issued, if at all, in 
certain exigencies and in small quantities. 

The same principles hold good in regard to soldiers' 
clothing as for that of other people, but " in selecting the 
material the chief points to be considered are its permea- 
bility, durability and the property it has of conducting 
and absorbing heat." It would be well if the undergar- 
ments were always in part, at least, of wool. The material 
of the uniforms and its weight should depend upon the 
exigencies of the service, considering both the locality and 
the season of the year. In cold weather wool should, of 
course, be chief ; in hot climates, the stout cotton fabric 
called khaki seems to meet the conditions most satisfac- 
torily. u The color of the material has an important 
bearing on the hygienic value of the clothing, and in 
regard to the absorption of heat exerts more influence than 
the material itself. . . White possesses very slight 
absorptive power compared to other colors, and, next to 
this in the scale, gray or pale yellow gives the best results. 
Gray is the best color for soldiers' dress on service, for 



382 A MANUAL OF HYGIENE AND SANITATION 

white is least suited to the field, as it soils so quickly. 
The khaki drill corresponds very closely with gray, as 
regards absorption power." 1 

The clothing should nowhere be so tight as to interfere 
with respiration or circulation or with free movement of 
the body. There should be a sufficiency of socks in each 
man's kit, for "a. good sock, kept clean, is a protective 
against sore feet." Boots or shoes should be comfortable 
as well as durable and waterproof. Leggings may often 
be used to advantage ; they may be of stout canvas, khaki 
or leather. Helmets or other head-dress should be light 
and well ventilated, and of a non-absorbent color. Ab- 
dominal bands of flannel are excellent protectives against 
digestive disturbances, if the men can be induced to wear 
them. Each kit should contain a rubber or waterproof 
blanket to protect the soldier from the dampness of the 
ground at night ; it can also be used as a cape in rainy 
weather. The weight of the kit, arms, accoutrement, 
etc., is often excessive, and should be kept as low as 
possible. In some armies as much as seventy pounds is to 
be carried by each soldier. It should be so divided that, 
when on the march, as much of this as possible can and 
should be carried for the men, they retaining only their 
arms and water bottles. " Weights are most easily borne 
when the following points are attended to : 1. They must 
be as near the centre of gravity as possible. 2. The 
weights must in no case compress the lungs, or interfere 
with the respiratory movements or the elimination of car- 
bon dioxide, or hinder the transmission of blood through 
the lungs, or render difficult the action of the heart. 3. 
No important muscles, vessels or nerves should be pressed 

1 Notter and Firth, p. 955. 



MILITARY HYGIENE. 383 

upon. 4. The weights should be distributed as much as 
possible over several parts of the body." l 

This means that the pressure will be most advanta- 
geously put upon the tops of the shoulder-blades and upon 
the hip-bones and sacrum. 

The disposal of the wastes of a camp involve one of its 
gravest problems. If it is a permanent post and the men 
are quartered in barracks with a sufficient water-supply, 
it may be best to construct a complete sewerage system. 
But where the encampment is temporary, the difficulties 
are greatly increased. Even though the camp is strictly 
policed, as it always should be, and the garbage and 
similar wastes destroyed by fire or burial, there remains 
the disposal of the excreta of large numbers of men, which, 
if neglected, is almost certain to become a source of 
infection. 

The customary sinks are not only liable to pollute the 
ground-water and perhaps the water-supply of the camp, 
but are a constant offence to the senses, and we now 
know that infection may be carried by flies directly from 
them to the food in the kitchens and mess-tents. Where 
used, their contents should be covered thrice daily by a 
layer of fresh earth or lime, and when the contents reach 
within two feet of the surface, they should be filled with 
earth and new ones opened. A medical officer has recently 
suggested that instead of using earth or lime for a covering 
a quantity of dry grass or straw be spread over the con- 
tents and burned two or three times a day. This would 
not only serve to disinfect the surface and sides of the 
trench by fire, but the ashes of the straw would form a 
loose covering of several inches' thickness which would 

1 Notter and Firth, pp. 961, 962. 



384 A MANUAL OF HYGIENE AND SANITATION. 

completely conceal the subsequent additions and at the 
same time effectually protect all the contents from the 
access of flies. 

However, it will be wiser to do away with the sinks 
altogether and to provide measures whereby the excreta 
can be at once chemically disinfected and then removed 
beyond the limits of the camp. Theoretically, the tub or 
pail system would seem to be available, if proper dis- 
cipline and supervision could be had ; but the recent 
experience in certain camps rather proves it to be unsatis- 
factory. Unless the contents are disinfected immediately, 
the soil about the camp will be almost certainly polluted 
and infected when the receptacles are removed for empty- 
ing, and the flies will also be as bad as at the sinks. If 
the tubs should be partially filled before use with a disin- 
fectant, and if they should have close-fitting covers which 
would only be removed at the time of use, the objections 
to them would be diminished, but would still persist in 
part. 

The board of medical officers already referred to have 
recommended, and the Surgeon-General and Adjutant- 
General have adopted the recommendation^ that the ex- 
creta be received into a large galvanized iron trough 
partially filled with an active disinfectant solution, prefer- 
ably milk of lime on account of its combined efficiency and 
cheapness. The trough is to be located in a suitable 
building, and when full or at regular intervals is to be 
emptied by means of a pumping cylinder into a large water- 
tight tank on a wagon, similar to the ordinary odorless 
excavating apparatus. It is probable that such appa- 
ratus under proper supervision will prove as efficient and 
practicable as any that can be devised short of a well-con- 
structed system of sewers involving water-carriage, the 



MILITARY HYGIENE. 385 

installation of which is obviously not feasible in a tempo- 
rary camp or in one not having an abundant water-supply. 

Space does not permit of a full discussion of military 
hospitals. At permanent posts they may have almost all 
the equipment and conveniences of the best city hospitals, 
but in the field in actual service much must be foregone. 
This often leads to censure from the uninformed and 
where censure is not deserved. But commanding officers, 
especially of the medical service, should foresee every 
emergency and provide for it as far as possible, overrating 
rather than underrating the probable needs and demands 
upon the hospital staff, and providing for the comfort as 
well as the necessities of the sick and wounded. The 
knowledge that typhoid fever, for instance, is almost cer- 
tain to occur and become epidemic in any camp of consid- 
erable extent or duration should compel preparation for 
the proper treatment of this disease in so far as this is 
possible in a field hospital. The trained nurse has proved 
her value in army hospital work, and has now a place in 
the regular army medical service. The enlistment and 
training of a sufficient number of hospital stewards is also 
of great importauce, as is also the instruction of the sol- 
diers themselves as to the care of themselves in emergen- 
cies. Undoubtedly this latter instruction, meagre as it 
has been, and the u first-aid packets," with which each 
man was supplied, greatly contributed to the excellence of 
results among the regular troops in the late war. 

A thorough course in the fundamental principles of 
hygiene should be a part of the education of every soldier 
in the regular army, and especially should this subject be 
installed as one of the most important in the curriculum 
at West Point. If the graduates and future officers from 
this great military school were so instructed, it is more 

25 



386 A MANUAL OF HYGIENE AND SANITATION. 

than probable that the advice and suggestions of the medi- 
cal officers of the service would be more often accepted 
and enforced in the future than they have been in the past. 
Hospital teats are apt to be poorly ventilated and op- 
pressive in hot weather or climates. They should have 
every advantage of location, that the comfort as well as the 
health of the patients may be conserved. A ventilated 
hospital tent, devised by Captain E. L. Munson, M.D., 



Fig. 74. 




Munson ventilated hospital tent, adopted for United States Army. (The fly thrown 
back over false ridge-pole to show ventilation opening.) 

U. S. Army, has been adopted by the Board of Equip- 
ment on account of its advantages, chief of which are a 
better ventilation and a lowering of the temperature within 
to the extent of several degrees. 

Another valuable addition to the hospital service of the 
army has been the purchase and thorough equipment for 
the purpose of several hospital ships. The saving of life 
and alleviation of distress made possible by these vessels, 



MILITARY HYGIENE. 387 

when compared with the effects of conditions obtaining in 
the ordinary transport ships, are incalculable. 

The work of the soldier, while excessive at times, ordi- 
narily permits much leisure to the men, which, in turn, is 
conducive not only to attacks of homesickness and ennui, 
but to the development of injudicious and injurious habits. 
Consequently, anything that will profitably employ the 
attention and activities of the men when off duty is bene- 
ficial. For this purpose reading-rooms, athletic sports 
and the work of various trades may be mentioned. The 
ability to keep his men pleasantly and advantageously 
occupied is one of the qualities of a good commander, and 
medical officers should assist the latter in this respect 
whenever possible. 

The medical officer will also be watchful to guard against 
the causes of the diseases which are most prevalent in the 
army, viz., phthisis, heart disease, pulmonary diseases, 
typhoid, malaria and continued fevers, and, not least in 
importance, venereal diseases. The latter do much harm 
in most standing armies, and it is as a prophylactic to these 
that the occupation of time and energy referred to above 
is especially advantageous. So, also, must the chief sur- 
geon and his assistants keep oversight of the rations, 
water supplies, etc. They must inspect the men at regu- 
lar intervals, weighing and measuring them, and examin- 
ing for heart-strain or other circulatory disturbance ; they 
must select suitable places of encampment when on the 
march, caring for those who are overcome by the heat or 
exhausted ; they must see that the troops do not injudi- 
ciously expose themselves when overheated ; in fact, they 
must be fully as zealous and active as the commanding 
officer to maintain the entire command in its highest 
physical efficiency. 






CHAPTER XIII. 



VITAL STATISTICS. 



Science is classified knowledge. By arranging known 
facts and units into groups, and considering them from 
different points of view, we discover the scope of a par- 
ticular science, and are also led to the discovery of new 
facts. 

In hygiene it is necessary to have this classification of 
facts to know what progress we are making, for the true 
test of any sanitary procedure is its efficacy in preserving 
health and preventing disease, and we cannot know 
whether it is efficient or not unless we tabulate and study 
the results and at the same time eliminate disturbing 
factors. In this connection it is to be noted that our 
facts must be accurate and derived from sufficient experi- 
ence, and that the disturbing factors are especially liable 
to be numerous. 

It is evident that we may study disease by direct obser- 
vation at the bedside and at the 'post-mortem table, or by 
experiment ; and while our knowledge in the past has 
been gained principally by the former method, we now, 
since the advent of modern bacteriology, may further in- 
vestigate many diseases by reproducing them in suscep- 
tible animals. In this way we soon learn that some 
diseases are much more preventable than others, and we 
endeavor to discover the respective causes and predis- 
posing conditions of each that we may the more readily 



! 



VITAL STATISTICS. 389 

estimate their effects and take measures to restrict and 
prevent their action. 

Oar observations may be of two kinds : 1. By noting 
and comparing individual cases, or by following the track 
of a particular outbreak or epidemic. 2. By observing 
large classes and groups of men, which necessitates a 
record of births 3 marriages, diseases, and deaths. The 
consideration of such records constitutes the study of 
vital statistics, the most important object of which is, as 
Dr. Billings says, " to give warning of the undue increase 
of disease or death presumed to be due to preventable 
cause, and also to indicate the localities in which sanitary 
effort is most desirable and most likely to be of use." 
The reader will also notice how the study of vital statistics 
broadens out into the science of demography — the study 
of the life of people and communities. 

The national census reports now give statistical returns 
not only for the wards and other political divisions of 
some of our large cities, but also for so-called u sanitary 
districts," in which the population is chiefly made up of 
those of marked racial or other characteristics that in- 
fluence the vital problem. The study of such returns 
supplies much information and the explanation of many 
otherwise obscure phenomena in the vital statistics of a 
municipality. 

At this point it will be well to note certain elementary 
principles which must be observed in any statistical in- 
quiry, in order that the results of that inquiry may have 
any value whatever. These are : 

1. Our facts, or numerical units, must have precise, 
definite and constant characteristics. For example, in 
tabulating the death-rate or sick-rate from typhoid fever, 
every case used in the calculation must be accurately 



390 A MANUAL OF HYGIENE AND SANITATION. 

diagnosed and must be undoubtedly one of that disease. 
If there is any doubt as to preciseness, it is better to omit 
that unit. 

2. The units are to be arranged into groups. These 
groups must have dividing characteristics so definite that 
there can be no doubt into which group each unit will 
come. No unit must be in more than one group at one 
time. It is difficult to group complex facts so as to 
properly analyze them and to discover all possible phases. 

3. Having decided and arranged the groups, we must 
have a constant numerical standard by which the relation 
of the various groups to the total units may be expressed. 
It is generally 100 or some multiple of 100. 

4. We must determine the variation in the proportion 
or relation of the component groups to the whole in similar 
series of cases. While only an approximation to an inva- 
riable proportion may be had in any one series, it may be 
shown mathematically that as the number of units in the 
series increase there is a greater probability that the pro- 
portious will remain the same, and that we may calculate 
the limits of variation by Poisson's formula, as follows : 
If m be the number of units in one group in the formula 
m -f- n = q, and n the number in the other, the propor- 

77) 11 

tion of m to q will be — , and of n to q, -, and these propor- 

9. q 

tions will vary in succeeding series within the limits indi- 



, 12 m n 

cated by Z \> — 3 — • Consequently, the greater the value 

V2 m n 
a 3 'or the 

limit of variation from — and -. 



VITAL STATISTICS. 391 

Example : Suppose that in a series of 1000 cases of 
diphtheria 700 recover ; then, according to the above 
formula, the limit of variation in the next series of 1000 
similar cases would be 40, and the recoveries would be 
between 660 and 740 ; whereas, in a like series of only 
100 cases the limit of variation would be 13 and the 
probable recoveries would vary between 57 and 83. 

The arithmetical mean is usually employed in medical 
inquiries, though the increase in population is estimated 
by geometrical progression. The probable error or varia- 
tion from the arithmetical mean is about two-thirds 
(0.6745) of the mean error, which latter is the mean of 
the mean error in excess and the mean error in deficiency. 
The mean error in excess is the difference between the mean 
of the series and the mean of all the units of the series 
above the mean. The mean error in deficiency is the 
difference between the mean of the series and the mean 
of all the units below the mean. 

The relative value of two series is as the reciprocals of 
the squares of their probable errors. Thus if the probable 
error of series A is 10 per cent, and that of B. is 2 per 
cent., the value of A to B will be as jfa to J, or B will 
be twenty-five times as valuable as A. 

The relative value of two or more series is also as the 
square roots of the numbers of units in the respective 
series. From the above it is evident that the results 
from an average cannot be absolutely applied to any par- 
ticular case, for there is always the chance of such varia- 
tion as may be determined by Poisson's formula or by the 
estimation of the probable error. We apply averages to 
the aggregates of facts, and they will approach exactitude 
if they are founded on a sufficient number of facts. We 
must be careful in estimating the value of means and 



392 A MANUAL OF HYGIENE AND SANITATION. 

averages and in giving credit or blame accordingly. Dr. 
Guy says : u Averages are numerical expressions of 
probabilities ; extreme values are expressions of possi- 
bilities." 

Statistical results are frequently expressed by graphic 
representations (see Fig. 75), and these are very valuable, 
especially for class or similar demonstration. 

Fig, 75. 



G.O 
5.5 
5.0 
4.5 

4.0 
3.5 

8.0 
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_ tM o eo t- oo o» o t-i e* 52 ^i 
-t—oooooooooooooocooooooo-. o»Sgs 
oooooooooooooooooooooooooooooooooooooooooooooooooo 

^rH^rHtHiHiHrHi-li-li-li-irHr-iTHi-li-frHi-liHiHr-ir-lt-li-l 

Graphic chart, showing percentages of typhoid-fever deaths in total mortality 
in four cities. Unbroken line, Chicago ; lower line, New York ; short dashes 
Philadelphia ; long dashes, Boston. 

The numerical units employed in the study and the cal- 
culations of vital statistics are persons living and persons 
dead, and the groups into which these units are classified 
are characterized by such distinctions as age, sex, occupa- 
tion, locality, etc. The sources from which we derive our 
information regarding these units are two, viz., the census 
or count, which every civilized country makes period- 
ically, and the returns of births, marriages, deaths and 






VITAL STATISTICS. 393 

cases of contagious disease made to local governing sani- 
tary bodies, such as boards of health, etc. These latter 
returns localize the units and help especially in the classi- 
fication in which locality is a factor. 

The census returns give not only the population, but 
particulars as to sex, age, race, occupation, etc. Of these 
the age-record is most important, as the death-rate varies 
most according to age. 

The natural increment of a population is the excess of 
births over deaths, but the actual increment differs from 
this, however, according to the difference between emigra- 
tion and immigration. And as the rate of increase does 
not always remain the same, estimates of population at 
times other than of the census cannot be exactly accurate. 
Thus, we may have a lowered death-rate and yet a de- 
crease in both the natural and actual increment, owing to 
a greatly lowered birth-rate and to increased emigration, 
both of which may be primarily due to a long period of 
oppression or financial distress. However, to estimate 
the population for times other than the census year, we 
assume that the rate of increase, whether positive or nega- 
tive, that prevailed between the last two census enumera- 
tions will continue until the next is taken. 

Now, as populations increase in regular geometrical 
progression when the rate of increase is constant, which 
we assume, it can readily be shown that 

logarithm R = -^ (log. P' — log. P), where R is the 

annual ratio of increase, P the population of the census 
before the last, and P' the population of the last census. 
If we now multiply the logarithm of R, the annual ratio 
of increase, by the number of years since the last census, 
and add to it the logarithm of the last census (log. P r ), 



394 A MANUAL OF HYGIENE AND SANITATION 

we will have the logarithm of the population at the 
middle of the given year — e. g., 

8 ( log,of the p0p - 189Q — lQ g-P°P- 188 ° ) 4. l 0g8 p p. 1890 

= logarithm of the population on June 30, 1898. 

For the reasons already given, such an estimate will 
not be absolutely accurate, and it would, consequently, 
be well to have a census taken every five years for certain 
data. The more accurate the estimate for any year hap- 
pens to be, the more reliable will be the statistical results. 
It is also to be noted that in this country the census is 
taken at the middle of the year, and that death-rates, etc., 
are based on the population estimated, as above, for the 
middle of the given year. 

We may also estimate the population from a number of 
houses and use this as a check on the above estimate. 
The number of persons living in each house averages about 
the same for each city, but differs for different cities. 
Local authorities always tend to overestimate the popu- 
lation, and a police census is invariably too high. An- 
other method of approximately estimating the population 
in small and slowly increasing districts is to add to the 
population of the last census one-tenth of the difference 
between it and the population of the preceding census for 
every year since the last census. 

As has been stated, we get the number of births, mar- 
riages, deaths, etc., from the registration records, the 
proper data being furnished to the registration bureau by 
duly authorized persons. For instance, the law should 
require a burial permit for each death in order to identify 
the person and to guard against criminal acts or neglect, 
and the death certificate on which the burial permit is 
issued should give the name, sex, color, age, occupation, 



VITAL STATISTICS. 395 

and especially the cause of death of the deceased. The 
diagnosis concerning this last item should be as correct as 
possible, and the primary as well as the secondary cause 
of death should be given. And while it is difficult to 
determine the actual cause of death in many cases without 
a post-mortem examination, there is, fortunately, not much 
uncertainty usually in diagnosing the diseases of which 
we most want statistical information, especially the so- 
called preventable or infectious diseases. 

As a consequence of the above, the certificate as to the 
cause of death will need to be signed by some one compe- 
tent to determine that cause, viz., by an educated physi- 
cian ; and it is, therefore, necessary that the State should 
define who is and who is not an " educated physician. " 
And as this information and the other required returns 
which the physician makes, as well as his professional 
services in general, are for the sake and benefit of the 
citizens of the State, it is evidently to the State's interest 
that it be very careful and explicit as to the qualifications 
of the physicians whom it allows to practice within its 
borders. 

Another reason for the enforced return of a certificate 
and the issuance of a burial permit for every death is that 
this is about the only way in which it is possible to secure 
a record of all the deaths. Any system for collating the 
list of deaths only at the end of the year will omit from 
25 to 40 per cent, of the number. 

The gross death-rate varies with the size of the com- 
munity. Newly settled communities have a lower death- 
rate than older ones, because the proportion of adults is 
larger and of children smaller in the former. With large 
communities and short periods the probabilities of error 
are very great, and the longer the period the less likelihood 



396 A MANUAL OF HYGIENE AND SANITATION. 

of error. Birth-rates, marriage-rates and death-rates are 
usually calculated as rates per thousand of the popula- 
tion living at the middle of the given year, and are 
determined by multiplying the number of births, mar- 
riages or deaths by 1000, and dividing the product by 
the population. 

Fair death-rates are 9 to 16 per 1000 in rural districts 
and small villages ; 14 to 18 per 1000 in towns of 5000 
to 20,000 ; 17 to 20 in cities of 25,000 to 100,000, and 
18 to 21 in cities of over 100,000. If the death-rates are 
much lower than this, the chances are that the population 
has been overestimated or that all deaths have not been 
recorded. If more than this, there is probably some 
special cause for the high mortality. 

In statistical computations we must exclude the popu- 
lations and deaths in hospitals, prisons, etc., except for 
such of the inmates as belong to the district in which 
such institution is located. 

To find the weekly or daily death-rate, the number of 
deaths for the week or day must be divided by the so- 
called weekly or daily population: the weekly population= 

total population ,, -, ., , ,. total population 
1-^- ; the daily population = t-J- 

52.17747 ' . /FF 365.24226; 

The monthly population equals the daily population mul- 
tiplied by the number of days in the month. 

The zymotic death-rate is the rate from the seven prin- 
cipal zymotic or infectious diseases, viz., smallpox, 
measles, scarlatina, diphtheria, whooping-cough, fever 
(typhoid, typhus, or other continued fever), and diarrhoea. 1 
It is given per 1000 of population, and in the same way 
we can give the special rate for any particular disease. 
For example, the average annual zymotic death-rate for 

1 Wilson : Hand-book of Hygiene, 8th edition, p. 570. 



VITAL STATISTICS. 397 

England and Wales for the decade from 1861 to 1870 
was 4.11, for 1871-80 it was 3.36, and for 1881-90, 2.30, 
— a striking proof of the decided benefits following proper 
attention to hygiene and sanitation. 

The mortality from certain diseases is affected by age, 
sex, race, occupation, density of population, seasons, 
cyclical changes, etc. 

Contrary to the general rule, the rate of infant mortality 
is not expressed per thousand of population, but measured 
by the proportion of deaths of infants under one year to 
the births registered in that year, and is determined by 
multiplying the number of deaths by 1000 and dividing 
the product by the number of births. 

The infant mortality-rate is always high, owing to 
various causes, viz., early marriages and weakly parents, 
hereditary tendencies or diatheses, insanitary surround- 
ings and unfavorable social conditions, improper feeding, 
insufficient clothing, infant life insurance, etc. 

Death-rates vary greatly for the different ages, being 
much higher for the first five years of life. For this 
reason, it is well to express the death-rate of children 
under five as the rate per thousand of children under that 
age, rather than as a percentage of the total number of 
deaths. Otherwise, a town with a large number of chil- 
dren might apparently have an abnormally high death- 
rate. There might also be a difference in the death-rates 
of two localities due to sex-distribution, for the sexes 
differ in their susceptibility and resistance to the various 
diseases. More boys are born everywhere than girls, but 
more males die than females, so that the tendency is to a 
preponderance of the latter, except in newly settled coun- 
tries or localities. Age-distribution and sex-distribution 
favor a low mortality in rapidly increasing towns, new 



398 A MANUAL OF HYGIENE AND SANITATION. 

localities, and manufacturing districts ; in rural districts 
they tend to increase the death-rate. 

Consequently, when the death-rates of two or more 
towns or localities are to be compared, there must be cor- 
rections for age-distribution and sex-distribution. The 
mean annual death-rate of the country for the decade pre- 
ceding the last census for each age and sex is applied to 
the town or district, with age-distribution and sex-dis- 
tribution according to the last census. The total number 
of deaths thus calculated, multiplied by 1000, and divided 
by the population of the last census, gives the standard 
death-rate of that town. The mean annual death-rate of 
the country divided by the standard death-rate gives the 
factor for correction, which being multiplied by the re- 
corded death-rate of any year gives the corrected death- 
rate. The comparative mortality figure is determined by 
multiplying the corrected local death-rate by 1000 and 
dividing by the death-rate for the whole country, and 
only indicates that the same /population which gave 1000 
deaths in the whole country gave or would have given so 
many deaths in the town or district in question. 

The morbidity-rate or sick-rate of a community is diffi- 
cult to estimate, since there is usually no complete record 
and registration of cases of disease. Where returns are 
required to be made of the infectious diseases, the mor- 
bidity due to them may be determined in the same way 
as the mortality for the locality. It is estimated that 
there is a total of about two years' sickness in a com- 
munity for every death, and members of beneficial socie- 
ties are said to average about one and one-half weeks' 
sickness annually. In this connection, the following 
definitions are given of terms that are employed in discus- 
sions of vital statistics, especially in relation to longevity : 



VITAL STATISTICS. 399 

The mean age at death of a population is the average 
age at which death occurs in that population, and is indi- 
cated by the total of the ages at death divided by the 
number of deaths. Inasmuch as it depends largely on the 
age-distribution of the population, it is neither a good test 
of longevity nor of sanitary conditions, except when it is 
calculated or taken from life-tables for an entire generation. 

The probable duration of life is the age at which any 
number of children born will be reduced one- half, the 
chances thus being even that each will survive to that age. 

For a million children the probable duration of life is 
for males less than forty-five years ; for females, forty- 
seven years. 

The mean duration of life is the same as the mean age 
at death when the population is stationary as to age-dis- 
tribution and sex-distribution. Otherwise, it is indicated 
by the mean after-lifetime. 

The expectation of life is the mean after-lifetime of a 
person at any age, as indicated by a life-table, or, in other 
words, it is the average number of years which persons 
of that age continue to live. At birth it is identical with 
the mean duration of life, and " as applied to communi- 
ties, it is the mean lifetime of a generation of persons 
traced by the life -table method from birth to death, and 
is the only true test of the health of populations." Ac- 
cording to Dr. Parr, " a life-table is a barometer which 
indicates the exact measure of the duration of life under 
given circumstances, and is indispensable in gauging the 
influence of sanitary or insanitary conditions." 

The essential factors of a life-table are the number and 
ages of the living and the number and ages of those that 
die, and these factors are obtained from the mean popu- 
lation for each age and sex and from the total death 
returns between two censuses. 



CHAPTEE XIY. 

THE EXAMINATION OF AIR, WATER AND FOOD. 

In this final chapter the author has endeavored to ar- 
range a series of methods for the examination or analysis 
of the subjects respectively considered, in such a manner 
that any one who has had a little laboratory experience 
may be enabled to determine their hygienic couditions, 
sanitary influence or degree of purity, and this at the cost 
of a minimum of time and expense. 

The methods outlined have been selected from a variety 
of sources, and some have been especially modified for the 
purpose; so that while it is not claimed that they will give 
the absolutely accurate results desired by the professional 
bacteriologist or chemist, nor that they will suffice as a 
basis for expert testimony in court or to establish legal 
rights, it is believed that, if carefully carried out, they 
will not fail to yield the information sought for, viz., 
whether the sample of air, water or food examined is 
sanitarily pure or safe for use within the accepted limits. 

Only such apparatus is to be used as can be readily 
obtained or improvised without much expense, and every 
effort has been made to render everything clear to the 
student and reader, so that he may not hesitate to under- 
take the necessary investigation whenever occasion requires 
or an opportunity offers. 

For further details regarding any of the methods, should 
these be found necessary, reference may be made to the 



EXAMINATION OF AIR, WATER AND FOOD. 401 

text-books indicated, as they will render clear any points 
that may here seem uncertain or abstruse. 

Air. 

The solid impurities in the atmosphere may be col- 
lected for microscopical examination as follows : Tightly 
cork a large glass funnel and fill it with cracked ice. As 
the aqueous vapor of the air condenses on the exterior, 
the dust particles adhere to the moistened glass, and are 
carried down by the condensed water into a vessel placed 
below, in which they are allowed to settle. From this 
they are transferred by means of a pipette to clean slides 
and examined under the microscope. Dr. Dixon's ap- 
paratus may often be used advantageously, especially 
where it is desired to examine the dust in the air of a 
number of localities within a short time. 

To make a qualitative bacteriological examination the 
air may be drawn through sterilized glass tubes coated in- 
teriorly with gelatin. Bacteria and their spores, moulds, 
etc., adhere to this coating, and from each individual or 
group of individuals colonics develop, from which pure 
cultures and subsequent bacteriological experiments may 
be made; or the sterilized gelatin may be exposed in 
flat (Petri) dishes to the air for a short time to allow the 
bacteria, etc., to fall on the surface. The tubes or dishes 
are then covered and set aside to allow the colonies to 
develop. 

To make a quantitative bacteriological examination a 
known quantity of air may be drawn through a small 
tube filled with sterilized and pulverized sugar. The 
sugar is then transferred to tubes or flasks of melted and 
sterilized gelatin, and dissolving leaves the bacteria, 
etc., free to develop in the gelatin, which may be poured 

26 



402 A MANUAL OF HYGIENE AND SANITATION. 

out before cooling upon sterilized glass plates or Petri 
dishes. A temperature just sufficient to melt the gelatin 
will not be too warm to harm the bacteria. The number 
of colonies that develop may be assumed to represent the 
number of living micro-organisms in the volume of air 
drawn through the tube. 

Test for Carbonic-acid Gas, C0 2 . Prof. Boom's Modi- 
fication of Wolpert's Method. Make a mark on any test- 
tube, say one inch from the bottom. Fix the bulb of an 
atomizer to a small glass capillary tube, sufficiently long 
to reach to the bottom of the test-tube, and in such a 
manner that a definite quantity of air is forced from the 
bulb through the tube at each compression. To use : 
Fill the test-tube exactly to the mark with a saturated 
solution of lime-water, take the apparatus into the out- 
door air and find out how many compressions of the bulb 
are needed, driving the air slowly through the lime-water 
each time, to make the lime-water just turbid enough to 
obscure a pencil-mark on white paper placed beneath the 
test-tube and viewed from above. 

Then rinse out the test-tube, fill exactly to the mark 
again with lime-water, and repeat the process in the room 
the air of which is to be examined. We then assume 
that the out-door air contains the normal amount of C0 2 , 
0.04 per cent, (unless we happen to know the actual 
amount in the atmosphere at the time), and estimate the 
percentage of C0 2 in the air of the room by the following 
proportion: Let x = the percentage of C0 2 in the air of 
the room. Then the number of compressions of the bulb 
required in the outer air : the number of compressions 
required in the room : : x : 0.0 %. If the actual per- 
centage of C0 2 in the outer air is known, substitute this 
for the 0.04 per cent, in the formula. Care must be taken 






EXAMINATION OF AIR, WATER AND FOOD. 403 

in using this device not to draw any of the lime-water up 
into the bulb. 

A Modification of Angus Smith's Method. To a mod- 
erately large, wide-mouth bottle (one quart) fit a per- 
forated rubber stopper, the perforation being just large 
enough to admit the tip of a 1 c.c. pipette ; first fill the 
bottle with the air of the room by filling it with water 
and then emptying it in the room ; fit in the stopper and 
introduce 1 c.c. at a time of a standardized alkaline solu- 
tion, slightly colored with a few drops of a neutral alco- 
holic solution of phenol phthaleine ; close the perforation 
with a piece of glass rod and shake the bottle well after 
each addition of the alkali, noting when the color ceases 
to be discharged by the C0 2 of the contained air. Then, 
since the quantity used of the alkali solution indicates a 
certain definite amount of C0 2 : 

The number of c.c. used multiplied by the amount of 00 2 
each c.c. represents, multiplied by 100, and divided by the 
capacity of the bottle in c.c. less the number of c.c. of solu- 
tion used = x = the percentage of C0 2 in the air ex- 
amined. 

A suitable alkaline solution may be prepared as follows : 
Dissolve exactly 2.409 grammes of pure sodium carbonate 
(free from the water of crystallization) in one litre of 
distilled water. Only a fraction, say one-fourth or one- 
tenth, of this quantity need be made up at a time. Each 
c.c. of this solution is equivalent to 1 c.c. C0 2 . For 
use : To 10 c.c. of this solution add a few drops of neutral 
alcoholic solution of phenol phthaleine and dilute to 100 
c.c. Each c.c. of this dilute solution is then equivalent 
to 0.1 c.c. of C0 2 , and used as above will give close 
results. The phenol phthaleine is used as an indicator, 
as it loses its color as long as the C0 2 is absorbed and 



404 A MANUAL OF HYGIENE AND SANITATION. 

the alkalinity of the soda solution is destroyed. The 
stock solution should be kept in well-filled, tightly stop- 
pered bottles. Example : If 9 c.c. of the above dilute 
solution be used, and the capacity of the bottle is 1200 
c.c, then 

9j<0 : lXlOO = _90_ =x=s0>0766 
1200 — 9 1191 

the percentage of C0 2 in the air of the room. 

Pettenkofer's Method. Into a large, clean bottle filled 
as above with the air of the room, 50 c.c. of a clear solu- 
tion of lime (or barium hydrate) is introduced, the bottle 
stoppered and then well shaken so that the air may be 
thoroughly mixed with the lime-water. The strength 
of the lime-water, being unknown, is determined by 
means of a solution of oxalic acid of such a strength 
that 1 c.c. corresponds in alkalinity to 0.5 c.c. of C0 2 . 
(Such a solution is made by dissolving exactly 2.84 
grammes of pure crystallized oxalic acid in one litre of 
distilled water.) 

Into 25 c.c. of the stock lime-water in a beaker, this 
acid solution is run from a graduated burette until the 
alkalinity of the lime-water is just destroyed, the neutral 
point being indicated either by means of a few drops of 
phenol phthaleine solution in the beaker, or by turmeric 
paper, the latter being colored brown, and the phenol 
phthaleine retaining its color as long as the solution is 
alkaline. When the lime-water is exactly neutralized the 
exact amount of the acid solution used is noted. Then, 
after the time necessary to allow the complete absorption 
of theC0 2 in the testing bottle by the lime-water therein, 
viz., eight to ten hours, 25 c.c. of that lime-water is 
measured into a beaker, and its alkalinity exactly de- 
termined as above, by means of the oxalic-acid solution. 



EXAMINATION OF AIR, WATER AND FOOD. 405 

Now, inasmuch as part of the alkalinity of the lime- 
water which was in the bottle has already been neutral- 
ized by the carbonic acid in the air of the bottle, it will 
require less of the acid solution to neutralize the lime- 
water from the bottle than was required for the same 
quantity of stock lime-water, and as 1 c.c. of the acid 
solution corresponds to 0.5 c.c. of C0 2 , the difference 
in the amount of acid solution used expressed in c.c. will 
express the number of c.c. of C0 2 in the volume of air in 
the bottle. 

For, though each c.c. of acid solution is equivalent to 
only 0.5 c.c. of C0 2 , the loss of alkalinity of only one- 
half the lime-water primarily introduced into the bottle 
has been determined and the total loss of alkalinity would 
have to be expressed by multiplying 0.5 c.c. C0 2 by twice 
the difference in c.c. between the amount of acid used in 
testing the stock lime solution and that used in testing 
the 25 c.c. (one-half) of lime-water from the bottle. But 
twice 0.5 = 1. Therefore, the difference between the read- 
ings in the two tests gives the amount of C0 2 in the air 
in the bottle. The quantity of carbonic acid in the bottle 
having been thus determined and the capacity of the bottle 
found by measuring the quantity of water it will hold, 
the percentage of carbonic acid in the air examined is 
readily determined. 

Example : 25 c.c. of stock lime-water requires 30 c.c. 
acid solution ; 25 c.c. of lime-water from bottle requires 
27 c.c. acid solution. 

Therefore, 30 c.c. '■ — 27 c.c. = amount of carbonic acid 
in the bottle, which contains (for example, say) 2550 c.c. 

Then 3X100 300 _ ,„- . . . 

2550-50 = 2500 = °* 12 ? er cent - C ° 2 m the air 
of the room at current temperature and pressure. To be 



406 A MANUAL OF HYGIENE AND SANITATION. 

absolutely exact id the result, correction must now be made 
by reducing the results to the standard temperature and 
barometric pressure, but this is unnecessary in most cases. 
The absorption of the carbonic acid gas is more rapid 
if a solution of barium hydrate is used instead of the 
lime-water, but the latter is usually much more readily 
obtained. 

Water. 

To test for color, turbidity, etc., compare with distilled 
water, using tall glass jars and looking down through 
equal depths upon a white surface. The smell of a water 
may be detected by heating it to about 140° F. for a few 
minutes in a glass- stoppered bottle. This test may or 
may not indicate fecal contamination. Few polluting 
impurities, when only in moderate quantities, give any 
taste to water, and a dangerously polluted water may 
have a good taste. Iron in small quantities, one-fourth 
of a grain to a gallon, will give a taste to the water. 

Use caution in tasting suspicious waters. Aeration is 
indicated by the lustre of the water and by the presence 
of air-bubbles on the sides and bottom of the vessel. 

Test for Chlorine. Solutions required. (1) Standard 
nitrate of silver solution : to 1 litre of pure distilled water 
add 4.788 grammes of pure silver nitrate ; 1 c.c. of 
this solution is equivalent to 1 m.g. of chlorine. (2) 
Potassium chromate solution — a 5 or 10 per cent, solution 
of potassium chromate made up in distilled water free 
from chlorine. 

Process. To 100 c.c. of the water add a few drops of 
potassium chromate solution, and then run in from a 
burette or graduated pipette the silver solution, adding it 
drop by drop, and stirring the water with a glass rod. 



EXAMINATION OF AIR, WATER AND FOOD. 407 

Continue until a faint but permanent orange-red tint has 
been produced, showing that all the chlorine has combined 
with the silver, the persistent reddish color being due to 



Fig. 76. 



ijiENTZScSONS 



Bottle for collecting water at different levels. 

silver chromate. The number of c.c. of silver used indi- 
cates the number of milligrammes of chlorine in 100 
c.c, or parts per 100,000 ; this multiplied by 10 gives 
the number of milligrammes in one litre, or parts per 



408 A MANUAL OF HYGIENE AND SANITATION. 

1,000,000. If the water contains but little chlorine, 
accuracy will be furthered by evaporating 250 of the 
water to 50 c.c. over a water-bath, and proceeding as 
above; the result multiplied by 4 will give the amount of 
chlorine in one litre. 

Test for Nitrates. Solutions required. 1. Phenol- 
sulphonic acid : 6 grammes of pure carbolic acid ; 37 c.c. 
strong sulphuric acid, and 3 c.c. distilled water. 2. 
Standard potassium nitrate solution : Add 0.722 grammes 
of fused potassium nitrate to one litre of distilled water. 
Each c.c. of this solution contains 0.1 m.g. of nitrogen 
as nitrates. The water used in making the solution must 
be free from nitrates. 

Process. Evaporate 10 c.c. of the water to be examined 
(or 25 c.c. if it is presumably low in nitrates) just to dry- 
ness. Add 1 c.c. of phenol-sulphonic acid, stir with a 
glass rod, and add 1 c.c. of distilled water and three 
drops of strong sulphuric acid ; warm, and add 25 c.c. 
distilled water, being careful t not to dissociate and drive 
off any of the nitrates by too prolonged or excessive heat- 
ing ; then add ammonia until the fluid is strongly alka- 
line, and dilute with water to 50 c.c. 

Treat 1 c.c. of the standard solution in an exactly 
similar manner and compare the tints produced, placing 
them in two Nessler or other tubes of equal calibre, and 
diluting the darker until the tints match exactly, and cal- 
culating the amount of nitrogen present by the amount of 
dilution necessary — e. g., the tint from 1 c.c. of standard 
potassium nitrate solution is darker and needs the addi- 
tion of 50 c.c. more water — i. e., up to 100 c.c. There- 
fore, 100 c.c. : 50 c.c. : :0.1 m.g. N : x = 0.05 m.g., 
the amount of nitrogen as nitrates in the 10 c.c. of water 
examined. The test depends ou the fact that the phenol- 



EXAMINATION OF AIR, WATER AND FOOD. 409 

sulphoaic acid is converted by the nitrates into picric acid, 
which goes to form ammonium picrate upon the addition 
of the ammonia, thus giving a yellow tint to the water. 
The amount of picric acid and picrate formed and the 
consequent depth of color therefore depend on the amount 
of nitrates present in the water. 

Test for Nitrites. Solutions required. 1. Sulphanilic 
acid : dissolve 0.5 gramme of sulphanilic acid in 150 c.c. 
of dilute acetic acid, sp. gr. 104. 2. Naphthylamine 
acetate : boil 0.1 gramme of solid naphthylamine in 20 
c.c. of distilled water, filter through a plug of washed 
absorbent cotton, and mix the nitrate with 180 c.c. of 
dilute acetic acid. 3. Standard sodium nitrite solution : 
dissolve 0.275 gramme of pure silver nitrite in pure water 
and add a dilute solution of pure sodium chloride until a 
precipitate ceases to form, and dilute to 250 c.c. with 
pure water. For use, dilute 10 c.c. of this stock solution 
to 100 c.c. Each c.c. of the dilute solution contains 0.01 
m.g. nitrogen as sodium nitrite. Keep the solutions in 
the dark when not in use. All water in these solutions 
must be free from nitrites ; likewise all water used in 
tests, except the sample under examination. 

Process. Place 25 c.c. of the water to be examined in 
a cylindrical vessel, and in a similar vessel dilute 1 c.c. of 
the (diluted) standard sodium nitrite solution to 25 c.c. 
with nitrogen-free distilled water ; add to each vessel 2 
c.c. of first One and then the other reagent, using a sepa- 
rate pipette for each; compare the colors at the end of 
five minutes and estimate the amount of nitrites by dilut- 
ing the darker tint until it matches the lighter, and com- 
paring the respective volumes, as in the test for nitrates ; 
the result will give the quantity of nitrogen as nitrites in 






410 A MANUAL OF HYGIENE AND SANITATION. 

the water, and should not be over a trace. The above 
test is a very delicate one. 

Schuyten's Method. 1 " When 5 c.c. of a 1 per cent, 
solution of antipyrin in acetic acid (1 : 10) is added to a 
solution containing nitrites, a green color is produced." 
Measure 45 c.c. of the water to be examined into a 
Nessler tube and in another of equal calibre mix 1 c.c. 
of the standard sodium nitrite solution (dilute) with 44 
c.c. of distilled and nitrite-free water. To each tube add 
5 c.c. of the antipyrin solution. Allow to stand for one- 
half hour and compare as above. 

" This method will show the presence of one part of 
nitrogen as N0 2 in 20,000 parts, and while not as delicate 
as the other method, is not hindered by the presence of 
any of the ordinary contaminations in water. " 2 

Test for Hardness. Solutions required. 1. Soap solu- 
tion : dissolve 10 grammes of castile soap in one litre of 
weak (35 per cent.) alcohol. 2. Standard lime solution : 
dissolve 1.11 grammes of chemically pure calcium chlo- 
ride in 1 litre of distilled water ; 1 c.c. of this solution 
is equivalent to 1 m.g. of calcium carbonate. 

Process. Find out how much soap solution is needed to 
make a standard lather with 100 c.c. of distilled water, as 
follows : Place the water in a flask holding about 250 c.c, 
and run in the soap solution from a burette, a few drops 
at a time, corking and shaking the flask well after each 
addition ; the lather should have a depth of at least one- 
fourth of an inch and be permanent for five minutes. 
Then standardize the soap solution by diluting 5 c.c. of 
the standard lime solution to 100 c.c. with distilled water, 
and find out how many c.c. of the soap solution are neces- 
sary to make a permanent lather as above with it ; this 

1 Bergey's Hand-book of Practical Hygiene, p. 95. 2 Ibid. 



EXAMINATION OF AIR, WATER AND FOOD 41 1 

quantity, less the number of c.c. needed to make a lather 
with 100 c.c. of distilled water, represents the amount of 
soap solution that will neutralize 5 m.g. of calcium car- 
bonate or its equivalent. Lastly, determine in the same 
way the number of c.c. of soap solution necessary to make 
a permanent lather with 100 c.c. of the water to be ex- 
amined ; again subtract the quantity of soap solution 
necessary for 100 c.c. distilled water and estimate the 
amount of calcium carbonate or its equivalent present, 
as follows — e. g. y it takes 2 c.c. of soap solution to make 
a lather with the distilled water, and 12 c.c. with the 
diluted standard lime solution ; then 12 c.c. — 2 c.c. = 
10 c.c, which is equivalent to 5 c.c. of the standard lime 
solution, and accordingly each c.c. of the soap solution 
is equivalent to 0.5 c.c. of the standard lime solution, or 
to 0.5 m.g. CaC0 3 ; consequently, if 100 c.c. of the 
water examined require 17 c.c. of soap solution, it must 
contain (17 — 2) X 0.5 = 7.5 m.g. of calcium carbonate 
or its equivalent, or 75 m.g. to the litre. 

Tests for Lead, Copper, and Iron. To 50 or 100 c.c. 
of water in a white porcelain dish, or in a tall glass jar 
over a white paper, add a few drops of ammonium sul- 
phide ; a dark coloration or precipitate indicates the pres- 
ence of either lead, copper or iron, due to the formation 
of their respective sulphides. Then add a few drops of 
hydrochloric acid ; if the color disappears iron only is 
present ; if it persists lead or copper is present. In the 
latter case add a few drops of acetic acid and about 1 c.c. 
of a strong solution of potassium cyanide ; if the color 
disappears it is due to copper ; if it persists it is due to 
lead. If lead only is present the above test will detect 
one-tenth of a grain per gallon. The above tests may be 
corroborated as follows : Partly fill two test-tubes with 



412 A MANUAL OF HYGIENE AND SANITATION. 

the original water; to one add a little potassium chromate 
solution; an opacity and the deepening of the color to 
canary yellow indicate lead. To the second add a drop 
of hydrochloric acid and a few drops of potassium ferro- 
cyanide solution; a blue color indicates iron, either ferrous 
or ferric; a bronze or mahogany -red color indicates copper. 

Quantitative tests for the above metals may be made by 
making standard solutions of the respective elements, 
treating a measured quantity of the original water with 
the proper reagent as indicated above, and comparing the 
color produced with that given by a definite quantity of 
the respective standard solution. 

Test for Phosphates. Solution required. Ammonium 
molybdate : dissolve 10 grammes of molybdic anhydride 
in 41.7 c.c. of ammonia (sp. gr. 0.96) and pour slowly 
into 125 c.c. of nitric acid (sp. gr. 1.20); allow to stand 
in a warm place for several days until clear. 

Process. Slightly acidulate 500 c.c. of water with nitric 
acid, evaporate to 50 c.c, and add a few drops of ferric 
chloride and ammonia to slight excess ; filter, dissolve 
the precipitate in the smallest possible quantity of nitric 
acid and evaporate to 5 c.c; heat nearly to boiling, add 
20 c.c of ammonium molybdate solution ; keep the solu- 
tion warm for one-half hour. If there is an appreciable 
quantity of precipitate, collect it on a small weighed filter- 
paper, wash with distilled water, dry at 100° F., and 
weigh. The weight of the precipitate multiplied by 0.05 
gives the amount of phosphorus tetroxide (P0 4 ) in the 
500 c.c of water. 

Test for Free and Albuminoid Ammonia. Wank- 
lyn's Method. Solutions required : 1. Standard ammo- 
nium chloride solution : dissolve 0.382 gramme of pure 
dry ammonium chloride in 100 c.c. ammonia-free water. 



EXAMINATION OF AIR, WATER AND FOOD. 413 

For immediate use dilute ] c.c. of this standard stock 
solution up to 100 c.c. with ammonia-free water ; each 
c.c. of the dilute solution contains 0.01 m.g. of nitro- 
gen as ammonia. 2. Alkaline potassium permanganate 
solution : dissolve 200 grammes of potassium hydrate (in 
sticks) and 8 grammes of potassium permanganate in 1 
litre of distilled water, evaporate to about 750 c.c. to 
drive off the ammonia present, and make up to 1 litre 
again with ammonia-free water. To make ammonia-free 
water, add about 1 grain sodium carbonate to the litre of 
distilled water and boil until about one-fourth is evapor- 
ated. 3. Nessler's reagent : dissolve 1.5 grammes of 
potassium iodide in 10 c.c. of distilled water and 1.7 
grammes of mercuric chloride (HgCl 2 ) in 30 c.c. of dis- 
tilled water; add the mercuric chloride solution to the 
potassium iodide until a permanent precipitate is formed, 
and then dilute to 100 c.c. with a 20 per cent, solution 
of sodium hydrate, add the mercuric chloride solution 
till a permanent precipitate again forms, and allow to 
stand until clear; this reagent gives a brown or yellowish- 
brown coloration if ammonia be present in water, and 
improves on keeping. 

Process. Place 500 c.c. of the water to. be examined 
in a retort, connect with a condenser, and boil gently so 
that the water may distil over slowly. The retort and 
condenser should have been thoroughly rinsed with am- 
monia-free water. Collect the distillate, 50 c.c. at a 
time, in Nessler tubes, add 2 c.c. of Nessler's reagent to 
each 50 c.c, and determine the amount of ammonia or 
nitrogen in each as follows : Place in another Nessler tube 
50 c.c. ammonia-free water and 2 c.c. Nessler's reagent, run 
in from a burette the dilute standard ammonium chloride 
solution until the color exactly matches that of the first 



414 A MANUAL OF HYGIENE AND SANITATION. 

50 c.c. of the distillate. Repeat the process with each 50 
c.c. of distillate until the test shows no more ammonia is 
coming over from the retort. The total amount of ammo- 
nium chloride solution used indicates the total amount of 
nitrogen of the free ammonia. Usually all the free am- 
monia will come over in the first 150 or 200 c.c. of dis- 
tillate. Compare the colors by looking down through the 
tube on a white surface. If the first 50 c.c. gives a pre- 
cipitate with the Nessler reagent it must be diluted and 
the amount of nitrogen estimated from the diluted distil- 
late. The free ammonia being determined, allow the 
retort to cool and add to the water remaining in it 50 
c.c. of the alkaline permanganate solution. This con- 
verts a certain proportion of the nitrogenous organic 
matter of the water into ammonia; distil as before, esti- 
mating the amount of nitrogen in each 50 c.c. of the dis- 
tillate until no more ammonia comes over. The amount 
of ammonium chloride solution thus used will indicate the 
nitrogen of albuminoid ammonia, and the total amount of 
ammonium chloride solution used in the whole process 
gives the nitrogen of the free and albuminoid ammonia 
in one litre of water. 

The importance and relative value of the results of the 
foregoing tests in determining the purity or safety of a 
drinking-water, have already been given in Chapter V. 
on pages 193 to 196, inclusive. 

Food. 

Milk. Good Milk. Characteristics : Ivory white, 
opaque, neutral or slightly alkaline reaction, no sediment, 
no unusual or offensive taste or odor, sp. gr. 1029 or 
above; cream, 10 to 40 per cent, by volume; fats, 3 per 
cent, or more; total solids, 12.5 per cent, or more. 



EXAMINATION OF AIR, WATER AND FOOD. 415 

Water is indicated by low specific gravity and by low 
percentage of cream. 

Skimming is indicated by a slightly raised specific 
gravity (2°), by a low percentage of cream, and by a 
poor color, though the deterioration in color may be dis- 
guised by the addition of annotto, etc. 

Watering and skimming are indicated by lowered spe- 
cific gravity, by low percentage of cream, aud by poor color. 

The specific gravity is determined by the lactometer, 
in using which correction must be made for temperature, 
provided the latter varies much from 60° F., the standard. 

The percentage of cream is determined by the cream 
gauge or creamometer; the milk should be allowed to 
stand in the creamometer for at least eight to ten hours, 
and should be covered. 

A very high percentage of cream tends to lower the 
specific gravity theoretically; but when a milk is rich in 
fat it is also rich in solids not fat. 

An acid reaction, unless very slight, indicates souring 
of the milk or the addition of some preserving acid. A 
strongly alkaline reaction indicates the addition of some 
substance like chalk, sodium carbonate, etc., to increase 
the specific gravity. Such addition is verified by an ex- 
cess of total solids, and by the effervescence of the latter 
— after drying — upon the addition of a drop or two of 
hydrochloric acid. 

To determine the percentage of total solids : Weigh a 
small evaporating dish, preferably platinum, add 5 to 10 
c.c. of milk, and weigh dish and milk to get weight of 
milk; evaporate to dryness over water-bath, completing 
the drying in a water-oven until there is no further loss 
of weight; weigh dish and contents (total solids); subtract 



416 ^ MANUAL OF HYGIENE AND SANITATION. 

weight of dish, multiply by 100, and divide by weight of 
milk. Result : the percentage of total solids. 

To determine the percentage of ash : Ignite the total 
solids over the naked name until all black specks have 
disappeared; cool and weigh; multiply weight of ash by 
100, and divide by weight of milk. Result : percentage 
of ash. 

To determine the percentage of fats : Proceed as above 
with 10 c.c. of milk, and evaporate until the residue is a 
tenacious pulp, extinguish the flame, fill the dish half- 
full of ether, stir and pound the residue thoroughly with 
a glass rod, decant the ether and filter it through a small 
filter- paper, reserving the filtrate; add more ether to the 
residue, stir as before, and filter, repeating the process 
three times or till the residue is perfectly white; wash 
the filter-paper well with ether, collect it and add to the 
preceding filtrate; evaporate the ether filtrate until only 
the fat remains and its weight is constant; weigh the fat, 
multiply by 100 and divide- by the weight of the milk. 
Result : percentage of fat. 

This method, when carefully performed, is said to be 
fully as accurate as the extraction (Soxhlet) method, and 
does not require the more expensive apparatus of the 
latter. If the residue from which the fat has been ex- 
hausted is carefully dried on a water-bath at 100° C, 
until there is no further loss by evaporation, its weight 
will be that of the " solids not fat " of the milk. 

Centrifugal method: Where a medical centrifuge is 
available for use, the following method for the fat- 
determination will be found to give results that are 
probably accurate to within one-fifth of 1 per cent, of 
fat: 

Two solutions are necessary : 1. Fusel oil, 37 c.c. ; 



EXAMINATION OF AIR, WATER AND FOOD. 41 7 

wood or methyl alcohol, 13 c.c; hydrochloric acid, 50 
c.c. 2. Sulphuric acid, sp. gr. 1.83. 

Iuto the milk bottle, which is made to fit the centrifuge 



Fig. 77. 




Bottle for determining percentage of fat by means of the centrifuge. 

and which has a long graduated neck, 5 c.c. of the milk 
to be examined is introduced by means of a pipette, and 
to this 1 c.c. of the alcohol solution (1) is added and the 

27 



418 A MANUAL OF HYGIENE AND SANITATION. 

mixture well shaken by hand. The sulphuric acid is then 
added, little by little, with frequent shaking, until the 
bottle is filled to the topmost (zero) graduation. It is 
then rapidly whirled in the centrifuge until only the fat 
occupies the neck as a clear layer, when the actual per- 
centage can be read from the graduations. When the 
milk is very rich — i. e., containing more than 5 per cent, 
of fat — it will be necessary to dilute the milk with an 
equal volume of water, and then to multiply the result 
by 2. Likewise, cream should be diluted with four parts 
of water and the result multiplied by 5. The same prin- 
ciple is employed in the Babcock and other cream testers 
now largely used by dairymen, etc. 

The extraction method : l " About 10 grammes of milk are 
carefully weighed in a glass or porcelain capsule and 
mixed with about 10 grammes of freshly ignited sand, 
pumice-stone, or asbestos, and evaporated to dryness on a 
water-bath. The dish with its contents is then finely 
pulverized and transferred to a Soxhlet extraction appa- 
ratus and the fat extracted with ether for at least five 
hours. The ether extract of the fat is then evaporated 
to dryness on a water-bath and the residue dried to con- 
stant weight (at 100° C.) and weighed. The increased 
weight of the flask (of the Soxhlet apparatus) will repre- 
sent the fat in the 10 grammes of milk." 

A Soxhlet apparatus is so constructed that a quantity 
of ether is repeatedly evaporated and condensed in it 
without loss, the condensed ether being made to percolate 
through substances placed in the upper part of the appa- 
ratus and to extract therefrom soluble matters, such as fat, 
which are collected in a small flask below, and from 
which the ether can finally be evaporated. 

1 Bergey's Hand-book of Practical Hygiene, page 129. 






EXAM IN A TION OF A IB, WA TER A XD FOOD. 4 1 9 

Test for annolto : A percentage of cream considerably 
lower than the color of the milk would indicate justifies 
the suspicion that some coloring matter has been used. 
This is frequently annotto. 

Coagulate one ounce of milk with a few drops of acetic 
acid and heat; strain, and press out the excess of liquid 
from the curd; triturate the curd in a mortar or dish 
with ether, decant ether and add to it 10 c.c. of a 1 per 
cent, solution of caustic soda; shake, and allow to sepa- 
rate; pour off the upper layer into a porcelain dish, put 
in two small disks or strips of filter-paper; evaporate 
gently. Annotto will dye the disks an orange or buff 
color. Moisten one disk with dilute sodium carbonate to 
fix the color; touch the other disk with a drop of stan- 
nous chloride. Annotto will give a rich pink color. 
This test is sensitive to oue part of annotto in 1000 of 
milk, and with milk in any condition. 

Test for boric acid : Upon igniting the total solids, boric 
acid or boron gives a greenish tinge to flame. Place in a 
porcelain dish 5 c.c. of milk, one drop of strong hydrochloric 
acid and two drops of a saturated tincture of turmeric. 
Dry on a water-bath, remove as soon as dry; cool, and 
add one drop of ammonia on a glass rod. A slaty-blue 
color, changing to green, is given if borax is present. 
This test will show one one-thousandth grain of borax. 
Less will give the green color, but not the blue. 

Test for salicylic acid and salicylafes. (Bergey). Dilute 
the milk (100 c.c.) with an equal bulk of distilled water 
at 60° C. ; precipitate with eight drops of acetic and eight 
drops of a solution of mercuric oxide in nitric acid; shake 
aud filter. To the filtrate add 50 c.c. of ether, which 
takes up the salicylic acid; decant, and filter the super- 
natant ether. Evaporate this filtrate nearly to dryness, 



420 A MANUAL OF HYGIENE AND SANITATION 

and add a few drops of highly diluted neutral ferric chlo- 
ride. A violet color indicates the presence of salicylic 
acid, the depth of color increasing with the amount. 

To test for salicylic acid in butter, it is first treated 
with sodium carbonate and the homogeneous mixture 
acidulated with sulphuric acid, and then shaken up with 
a mixture of equal parts of ether and petroleum ether; 
the supernatant ether filtered and treated as above. 

Test for formaldehyde. (Bergey.) Add an equal vol- 
ume of water to the milk or butter to be tested, place in a 
flask on a steam-bath and distil over about one-fourth 
the total volume. Treat 10 c.c. of the distillate with two 
drops of ammoniacal silver solution (made by dissolving 
one gramme of silver nitrate in 30 c.c. of distilled water and 
adding ammonia until the precipitate that first appears is 
redissolved, theu diluting to 50 c.c. with water). If 
formaldehyde is present, it causes a black cloud in the 
distillate after standing for several hours in the dark. 

Butter and Oleomargarine. Good butter should have 
good taste, odor and color; it should not be rancid, and 
should not contain too much water nor salt, nor should it 
have any added coloring matter. The average composi- 
tion should be about as follows : Fat, 82 per cent. ; 
casein, 2 per cent, (not over 3 per cent.); ash or salts, 2 
per cent.; water, 13 per cent. Butter fat is a compound 
of glycerin with certain fatty acids, some of them volatile 
and soluble in hot-water, others non-volatile and insoluble 
in hot-water. 

Oleomargine consists of ordinary animal or vegetable 
fats, melted, strained, cooled with ice, worked up with 
milk, colored, and salted. These fats are usually beef 
or mutton fat, lard, or cotton-seed, palm, or cocoa nut 
oil. 



EXAMINATION OF AIR, WATER AND FOOD. 421 

If care and cleanliness are observed iu the manufacture, 
oleomargarine is not harmful or innutritious, but it should 
not be sold as butter. 

Fraud is to be detected by observing the difference in 
composition and properties of the fats. For instance : 

Butter Fat. Beep Fat, etc. 

1. The specific gravity is very rarely Beef fat, etc., is never above 904.5. 
below 910, never below 909.8. 

2. The soluble, volatile fatty acids Rarely more than % per cent., never 
average between 6 and 7 per cent., above % per cent. 

never below 4.5 per cent. 

3. The insoluble fatty acids form Generally about 95 per cent, 
about 88 per cent, of the total weight 

of butter fat. 

4. The melting-point of the fat varies Barely, if ever, above 82° F. 
from 86° to 94° F. ; is usually from 88° 

to 90° F. 

5. Is readily and completely soluble Less so and leaves a residue. 
in ether. 

6. Under the microscope pure butter The contours of the small oil globules 
fat consists of a collection of small oil are less distinct, and the larger ones are 
globules, with an occasional large one. more numerous and irregular in size. 

No crystals, except when the fat has Crystals of the non-volatile acids are 

been melted. often seen. 

To determine the sjoecifie gravity ; Melt a quantity of the 
butter in a beaker in a water- bath at about 150° F. 
After a time, when the fat is perfectly clear and trans- 
parent, carefully decant the fat from the lower stratum 
of water, curd, and salt into a fine filter; collect the fil- 
trate and pour into a specific-gravity bottle, which has 
been previously weighed, both when empty and when 
filled with distilled water at 100° F. See that the bottle 
is exactly full of the fat, wipe clean, and weigh when the 
temperature is as near 100° F. as possible, because solidi- 
fication soon begins below this temperature. Subtract the 
weight of the bottle, divide by the weight of the water 
which the bottle contains, and multiply by 1000; the 
result is the specific gravity. 



422 A MANUAL OF HYGIENE AND SANITATION. 

To find the melting-point : Pour a little melted fat into 
a small test-tube (2 ;/ xJ") and cool. Partly fill two 
beakers of unequal size with cold water; place the test- 
tube in the smaller (taking care to allow no water to 
mix with the fat), and the smaller in the larger, and 
gently heat the outer beaker. Suspend a thermometer in 
the smaller, near the test-tube, and note the temperature 
when the fat begins to melt; this is the melting-point. 

To determine the percentage of insoluble Onon-volatile) 
fatty acids: To 6 grammes of butter fat add 50 c.c. of 
alcohol containing 2 grammes of caustic potash (KHO) 
and boil gently for fifteen or twenty minutes to saponify 
the fat. Dissolve the soaps thus formed in 150 to 200 
c.c. of water, and decompose with about 25 c.c. of dilute 
hydrochloric acid. The separated fatty acids are poured 
upon a weighed filter-paper, washed with two litres of 
boiling water, dried at 95° to 98° C. and then weighed. 
The weight of these insoluble fatty acids should not be 
over 90 per cent, of the weight of the butter fat. 

Flour and Bread. Wheat Flour. Characteristics : 
Almost perfectly white, smooth and free from grit; no 
mouldy or unpleasant odor; cohesive when lightly com- 
pressed; no signs of parasites under the microscope; water 
less than 18 per cent.; ash less than 2 per cent. 

To determine the percentage of water and ash; In a 
weighed platinum (or porcelain) dish place about 50 
grammes of flour, weigh, and dry over a water-bath for 
an hour or so; then complete the evaporation in a water- 
oven until there is no further loss of weight; weigh, sub- 
tract this weight, less the weight of the dish, from the 
original weight of the flour. Multiply the remainder by 
100 and divide by the original weight of the flour. The 
result is the percentage of water. Then ignite the dried 



EXAMINATION OF AIR, WATER AND FOOD. 493 

flour in the dish and incinerate till there are no longer 
any black particles and only the ash remains; cool, weigh, 
subtract weight of dish, multiply the remainder by 100, 
and divide by the original weight of the flour. The 
result is the percentage of ash. 

To determine the percentage of gluten : By means of a 
glass rod, mix a weighed quantity of flour with a little 
distilled water into a stiff dough; then repeatedly wash 
away the starch and soluble constituents, kneading the 
dough with the rod or fingers, and continuing until the 
wash-water comes away clear; the gluten and a small 
amount of fat and salt remain. Spread out on a weighed 
dish or crucible lid, dry in a water-oven, and weigh; 
multiply by 100 and divide by the original weight of the 
flour. The result is the approximate percentage of gluten. 
The gluten should pull out into long threads; otherwise, 
it is poor. 

An excess of water impairs the keeping quality and 
lessens the amount of nutriment in the flour. An excess 
of ash indicates the addition of mineral substances. A 
deficiency of gluten indicates that the flour is not pure 
wheat flour. Parasites and fungi especially affect or live 
in old or damp or inferior flour. 

To test for mineral substances : Shake a little flour in a 
test-tube with some chloroform, and allow it to stand for 
a few moments. The flour floats and any mineral matter 
sinks to the bottom, when it can be removed with a pipette 
and examined under a microscope. 

Wheat Bread. Characteristics : Fairly dry, light, 
and spongy; clean and nearly white; of pleasant taste; 
not sodden, acid or musty; ash not over 3 per cent.; no 
parasites or mouldiness; no flour other than wheat; but 
little, if any, alum; no copper sulphate. 



424 A MANUAL OF HYGIENE AND SANITATION 

Test for alum : Add 5 c. c. of a 5 per cent, tincture of 
logwood and 5 c.c. of a 15 per cent, solution of ammonium 
carbonate to 25 c.c. of water; soak a crumb of the bread 
in this for a few minutes; drain and gently dry. Alum is 
indicated by a violet or lavender color; its absence by a 
dirty-brown color on drying. 

Test for copper sulphate : Draw a glass rod dipped in a 
solution of potassium ferrocyanide across a cut slice of 
the bread; copper is indicated by a streak of brownish-red 
color. 

Test for ergot in flour or bread : Add liquor potassse ; 
a distinct herring-like odor (due to propylamine) is appre- 
ciable if ergot be present. 

An excess of water, an unnatural whiteness, and a low 
percentage of ash in bread indicate the addition of rice. 
Potatoes give an increased percentage of water and an 
alkaline ash. 



For further tests and details in work pertaining to a laboratory of hygiene the 
reader is referred to Fox's Examination of Food, Air, and Water, Kenwood's 
Hygienic Laboratory, and Bergey's Hand-book of Practical Hygiene. 



INDEX. 



A BSOKPTION of foods, 210 
ii. Accessory foods, 219 
Acetylene gas, 78 
Adulteration of foods, 240 
Air, 61 

bacteria in, 6^> 

collection of bacteria in, 401 

diseases caused by impure, 82 

examination of, 401 

filtration of, 99 

-propeller, 112 

purification by fire, 93 

saturation of, 71 

-supply, source of, 99 
Alcohol, 245 

indications for use and absten- 
tion, 246-248 

relationship of, to food, 245 
Alexins, 54 

Alum, use of, in purifying water, 
164, 176 

test for, 423 
Ammonia, " albuminoid," in water, 
194, 414 

"free," in water, 194, 413 

test for free and albuminoid, 412 
Amylopsin, action of, 208 
Anderson's process, 165 
Anemometer, 104 
Annotto, test for, in milk, 418 
Antiseptics, 299 
Antitoxins, 55 

methods of preparing, 58 

statistics of use of, 60 

theory of, 55 
Apparatus, steam disinfecting, 304 
Aqueous vapors, 64, 71 
Argon, 63 

Army medical officers, duties of, 
387 

rations, 380 



Artesian -water, 136, 148 

wells, 148 
Artificial ventilation, 100, 110 
Ashes, 337 
Aspiration, 102 
Atavism, 257 
Atmosphere, the, 61 

composition of, 61 

impurities in, 65 

of mines, 80 

of ships, 80 

weight of, 61 
Atmospheric contamination, extent 
of, 94 

index of, 94 
Autogenetic diseases, causes of, 29 



BACILLI, 37 
Backus heater, 118 
Bacteria as an index of purity of 
filtered water, 176 
atypical forms of, 37 
classification of, 37 
collection of, in air, 401 
definition of, 33 
differentiation of, 43, 44 
discovery of, 34 
in air, 66 
isolation of different species of, 

39 . 
parasitic, 47 

in sewer- gas, 78 
pathogenic, 47 
requirements of, 35 
saprophytic, 46 
Bacterial examination of air, 401 

of water, 191 
Bacteriology, 33, 34 
Barracks, construction and arrange- 
ment of, 373 



426 



INDEX. 



Bathing, 266 

rules for, 268 

sea-, 267 

time of, 268 
Baths, cold, 267 

Kussian, 270 

Turkish, 269 

warm, 269 
Beans, nutritive value of, 238 
Bedding, disinfection of, 318 
Beef, 229 

-fat, characteristics of, 420 

-tea as a stimulant, 243 
recipe for whole, 235 
Berkfeldt filter, the, 184 
Beverages, 248 

sanitary precautions concerning, 
249 
Bichloride of mercury, 306 
Bile, action of the, 208 
Boric acid, test for, in milk, 419 
Bread, 236 

test for alum in, 423 

for copper sulphate in, 423 
for ergot in, 424 
Broiling, 233 
Broths, 233 

Buchner, humoral theory of, 51 
Butter, 227 

examination of, 420 

-fat, characteristics of, 420 
Buttermilk, 223 



pALCIUM hydrate, 308 
\J Camp-hospitals, 373, 385 

pollution, 376 
Camps of detention, 334 

diseases of, 378 

disposal of excreta in, 383 

location of, 371 

of probation, 334 

of refuge, 334 

typhoid fever in, 375 

water-supply of, 379 
Carbohydrates, functions of, 215 

sources of, 214 
Carbolic acid, 307 
Carbonic acid, 63, 307 
effect of, 68 
excretion of, 69, 262 



Carbonic acid, poisoning by, 87 
Pettenkofer's test for, 404 
tests for, 402 
Carbon monoxide, poisoning by, 88 

proportion of, to nitrogen in 
diet, 212 
Care of school-houses, 292 
Carpets, etc., disinfection of, 319 
Census, the, 392 
Cereals, the, 235 
Cesspools, dangers of, 340 
Cheese, 227 
Chemical disinfectants, 305 

treatment of sewage, 364 
water purification by, 163 
Chloride of zinc, 308 
Chlorides in water, test for, 406 
Chlorinated lime, 305 

soda, 306 
Chlorine, 309 

or chlorides in water, 193, 406 

test for, 406 
Cisterns for rain-water, 138 
Clark's process, 162 
Cloak-rooms in school-houses, 290 
Closets, earth-, 341 

pail-, 341 

water-, 353 
Clothing, 270 

advantages of woollen, 271 

conveyance of infection by, 276 

disinfection of, 317, 318 

influence of, upon health, 275 

materials used for, 245 

of soldiers, 381 

purpose of, 270 

relative absorption of heat by, 
276 

sophistication of, 274 

tests for materials for, 274 
Coal-gas, composition of, 89 

poisoning by, 89 
Coffee, 243 

Cold baths, effects of, 267 
Columbia filters, 184 
Combustion products, 74 

influence upon health of, 87 
Comparative mortality figure, 398 
Consanguineous marriages, objec- 
tions to, 259 
Condensed rations, 380 



INDEX. 



427 



Construction and care of wells, 149 

of school-houses, 289 
Convected heat, 113 
Cooking, object of, 232 

of vegetables, 238 

thoroughness of, 211 
Copper sulphate, test for, in bread, 
423 

test for, in water, 411 
Corrosive sublimate, 306 
Cotton in clothing, 272 
Cowls, 101, 102 
" Cramps," cause of, when bathing, 

268 
Cream, digestibility of, 223 
Creolin, 308 
Cresols, the, 308 
"Crowd poison," 72 

effects of, 86 
Cubic space, 98 

Culture media, preparation of, 42 
reaction of, 38 
temperature of, 38 



DEATH-RATES, 395 
daily or weekly, 396 
of cities, 396 
standard, 398 
zymotic, 395 
Deep water, 136, 148 

wells, 148 
Deodorants, 299 
Detention at ports of entry, 324 
camps of, 334 

period of, in quarantine, 324, 
332, 333 
Devices for ventilation, 105 
Dietetics, 202 

aesthetic factors in, 202 
Differentiation of bacteria, 43 
Diffusion, 100 
law of, 62 
rate of, 100 
Digestion, hydrolysis in, 204 
physiology of, 203 
the gastric, 207 
the intestinal, 208, 209 
the salivary, 205 
Direct radiation, 128 
-indirect radiation, 129 



Diseases affecting animals used for 
food, 231 

classification of, 29 

definition of, 28 

and causes of autogenetic, 29 

due to impure air, 82 

to impure drinking-water, 152- 

158 
to respiratory vitiation, 86 

incubation-periods of, 294 

infectious, in schools, 293 

methods of combating inherited, 
257 
study of, 388 

transmissible by heredity, 258 
Disinfectant, definition of a, 298 
Disinfectants, chemical, 305 

comparative table of, 316 

physiological, 301 

thermal, 302 
Disinfecting apparatus, steam, 304 
Disinfection, 30, 298 

by dry heat, 304 

by fire, 302 

by formaldehyde, 312 

by hot-water, 303 

by steam, 302 

efficacy of, 300 

evidence as to, 301 

final, of rooms, 318 

in the sick-room, 317 

of bedding, 318 

of carpets, etc., 319 

of clothing, 317, 318 

of excreta, 307, 308, 317 

of infectious cases, 316 

of school-houses, 290, 294 

of spores, 301 

of vessels in quarantine, 330, 331 

personal, 317 

Schering's method of, 313 

thoroughness of, 300 

Trillat's method of, 312 
Disinfector, duties of a, 298 
Distillation of drinking-water, 177 
Domestic purification of water, 176 
Drinking-water, distillation of, 177 

infection by, 154' 

necessity for boiling, 184 

the examination of, 189, 406 
Drip-safes, 353 



428 



INDEX. 



Dry heat, disinfection by, 304 
Duration of life, mean, 399 
probable, 399 

of school-work, 282 
Duties of army medical officers, 

387 
Duty of physicians, 24 



EARTH-CLOSETS, 341 
Economy in heating, 114 
Eggs, 228 

Ejector sewerage system, 339 
Environment, influence of, 31 

on predisposed constitutions, 
258 
Enzymes, action of the, 203 
characteristics of the, 204 
of vegetable origin, 211 
the digestive, 203 
Estimation of radiating surfaces, 

131 < 
Examination of air, 401 
of butter, 420 
of drinking-water, 189, 406 
of flour, 422 
of food, 414 
of milk, 414 
Excreta, disinfection of, 307, 308, 
317 
disposal of, in camps, 383 
Exercise, 260 

amount necessary, 266 
effect upon brain development, 
265 ^ 
upon digestive functions, 264 
upon excretion, 262 
upon heart and circulation, 

264 
upon heat- production, 264 
upon muscles, 262 
upon respiratory organs and 
functions, 261 
importance of, 260 
Exhaust system, 131 
Expectant attention, danger of, 

252 
Expectation of life, 399 
Extent of atmospheric contamina- 
tion, 94 
External ventilation, 92 



FACTORS of ventilation, 94 
Fans, ventilating, 111, 112 
Farr, Dr. Wm., 20 
Fatigue, causes of, 265 
Fats, constructive property of, 217 
digestibility of, 216, 218 
functions of, 216 
properties of butter- and beef-, 

420 
sources of, 216 

to determine specific gravity of, 
421 
melting point of butter-, 421 
Fatty acids, to determine insoluble 

or non-volatile, 422 
Filters, action of sand-, 167 
cleaning of sand-, 175 
construction of sand-, lb9 
house-, 180 

material used in sand-, 171 
Filtration, 166 
of air, 99 
of rain water, 138 
of sewage, 364 
rate of, 175 

regulation of rate of, 169 
Fire, disinfection by, 302 
Fish, 230 

Fixtures, location of house-, 347 
v traps of house-, 347 
Flies as carriers of infection, 376 
Floor-space, 98 

Flour, characteristics of wheat-, 
422 
test for minerals in, 423 
to determine the ash in, 422 
the gluten in, 422 
the water in, 422 
Flues, hot-air, size of, 125 
Flush tank, Field's siphon, 302 
Food, 198 

cooking of, 210 
definition of, 198 
functions of, 198-201 
-principles, classification of, 199 

relationship in diet, 212 
-salts, function of, 218 

sources of, 219 
the amount necessary for life 

and health, 212 
the, of the soldier, 379 



INDEX. 



429 



Foods, absorption of, 210 

accessory, 219 

adulteration of, 240 

relative value of, 241 

use of preservatives in, 240 
Forbes sterilizer, the.. 177 

advantages of the, 179 
Forces of ventilation, 100 
Formaldehyde, 311 

as a deodorant, 316 

disinfection by, 312 

methods of using, 312 

production from methvl alcohol, 
313 

regenerators for vaporizing. 313, 
315 

solutions of, 312 

test for, in milk, 419 
Formalin, 312 
Formic aldehyde, 311 
Formula for problems in ventila- 
tion, 97 
Free pratique, 333 
Fruits, 239 
Frying, 234 
Fumigation, 319 
Furnaces, hot-air, 122 
Furs, 273 

GARBAGE, disposal of, 337 
Gaseous impurities, 67 
Gas-stoves and grates, 118 
Gastric digestion, 207 
Germ theory, 33, 47 

arguments for, 49 
Germicides, 298 
Gluten, to determine percentage of, 

422 
Glycogen, 215 
Graphic charts of statistics, 391, 

392 
Grate fires, open, 114 
Grates, ventilating, 115, 116 
Grinding, effect of, 236 
Ground-water, 136, 142 

current of, 144 

purification of, 143 



H 



ARD water, 139 

diseases due to, 153 



Hardness of water, 139, 195, 410 
permanent, 139 
temporary, 139 
test for, 410 
Headache in school children, 285 
Health, definition of, 28 

of soldiers, 374, 375, 378 
Heat, air-movement due to, 102 
convected, 113 
radiant, 113 
relative absorption by clothing, 

276 
transmission of, 126 
Heating by hot-air, 122 
hot-water, 127 
steam, 128 
Heredity, definition of, 254 
importance of observing laws of, 
255 
Hippocrates, 19 
Hospital ships, 386 

tent, the Munson, 386 
Hospitals, purity of air in, 97 
Hot-air flues, size of, 125 
furnaces, 122 
air-supply of, 124 
combustion of fuel in, 125 
limitations of, 126 
location of, 124 
requirements of, 122 
-water, disinfection by, 303 
heating, 127 
House drainage, 342 

drains, air inlets to, 346 
connection of, with sewer, 346 

with soil-pipes, 346 
construction of, 345 
the, 343 
-filters, 180 

classification of, 181 
dangers of, 180 
materials for, 185 
requisites of, 181 
self-cleaning devices for, 184 
-fixtures, connection of, to waste- 
pipes, 347 
quarantine, 335 
-warming, 113 
Humidity of warmed air, 126, 130 
Humoral theory, 54 
Hydrogen dioxide, 309 



430 



INDEX. 



Hydrogen peroxide, 309 

sulphide, 90 

symptoms due to inhalation of, 
90 
Hygiene, ancient, 20 

definition of, 17 

development of, as a science, 20 

military, 369 

order of study of, 24 

personal, 251 

progress in, 21-23 

reasons for study of, 24 

school, 281 

scope of, 17-19 



ICE-WATER, abuse of, 189 

1 purity of, l89 

Illuminating agents, influence of, 
76 
-gas, composition of, 89 
poisoning by, 89 

Illumination, apparatus for, 76 

Immunity, theories of, 54, 57 

Impure air, diseases due to, 82 
water, diseases due to, 152 

Impurities due to combustion, 74 
due to respiration, etc., 65 
gaseous, 67 
in air, 65 

mortality due to, 83 

Incubation -period of infectious dis- 
eases, 294 

Index of atmospheric contamina- 
tion, 94 

Indirect radiation, 128 

Infant-mortality, causes of, 397 
rate of, 397 

Infection by drinking-water, 154 
conveyance of, by clothing, 276 

Infectious diseases, causes of, 29 
disinfection of cases of, 316 

Influence of illuminating apparatus 
on health, 75 
of school-furniture, 286 

Inland quarantine, 333 

Inlets, fresh-air, to house drains, 
346 
location of ventilation, 108 
size of ventilation, 109 

Inspection, quarantine, 324 



Internal ventilation, 93 
Intestinal digestion, 208, 209 
Involution forms, causation of, 37, 

38 
Iron sulphate, 309 

test for, in water, 411 
Irrigation treatment of sewage, 366 



KEFIR, 224 
Koch's postulates, 51 
Koumiss, 224 



] ABARRAQUE'S solution, 306 
JJ Lake-water, 142 
Lead in water, 154, 196 

test for, in water, 411 
Leather, 273 

Level of ground-water, 144 
Life-table, factors of, 399 

-tables, value of, 399 
Light, 276 

germicidal effect of, 278 

importance of an abundance of, 
279 

influence of, upon health, 276 
upon metabolism, 279 

penetration of sun-, 277 

'therapeutic effects of sun-, 278 
Lighting agents, influence of, 75 

increased by prismatic devices, 
279 

of school rooms, 289 
Lime, chloride of, 305 

chlorinated, 305 

milk of, 308 
Limit of permissible respiratory 
impurity, 95 
soil pollution, 144 
Linen in clothing, 273 
Location of school-houses, 290 

of ventilation inlets, 108 
outlets, 106 

of wells, 150 
Loomis-Manning filters, 186, 187 



MALARIA and typhoid fever, 
377 
Marriage, proper age for, 256 



INDEX. 



431 



Marriages, objections to consan 

guhieous, 259 
Mastication, value of, 206, 210 
Mean after-lifetime, 399 

age at death, 399 

duration of life, 399 
Meat, characteristics of good, 229 

composition of, 229 
Meats, cooking of, 232 

digestibility of various, 230 

diseased, 231 
Mercury, bichloride of, 306 
Meters, water, 135 
Micrococci, 37 
Military hygiene, 369 

importance of, 370 
Milk, 221 

as a cause of disease, 224 

as a source of infection. 22-4 

care and preparation of, 222 

characteristics of good, 226, 414 

of lime, 308 

test for annotto in, 418 
for boric acid in, 419 
for formaldehyde in, 419 
for salicylic acid in, 419 

the use of preservatives in, 
226 

to determine the ash in, 415 
the fats in, 416-418 
the total solids in, 415 
Mines, atmosphere of, 81 
Mortality, cause of infant-, 397 

due to impurities in air, 84 

rate of infant-, 397 

-rate, typhoid, an index of water- 
purity, 156 

-rates, 396 
Movement of heated air, 102 
Munson hospital tent, the, 386 
Mutton, 230 



NATURAL ventilation, 100 
Nervous diseases in school- 
children, 285 
Nessler's reagent, 413 
Nitrates in water, 195, 408 

test for, 408 
Nitrification of organic matters, 
195 



Nitrites in water, 195, 409 

Schuvten's test for, 409 

test for, 409 
Nitrogen, 63 

proportion of, to carbon in diet, 
212 
Nuts, 239 



AAT-MEAL, 235 

yj Objections to stoves, 117 

Oil- stoves, 120 

Oleomargarine, 420 

Ophthalmia, contagious, in schools, 

297 
Organic excretion, 72 

matters in water, 195 
Outlets, location of ventilation, 106 
Overwork, effects of, in school, 282 
Oxygen, 62 

absorption of, 262 



DAIL-CLOSETS, 341 

I Pancreatic juice, the, 208 

Paraform, 312 

Paraformaldehyde, 312 

Parasites, 47 

Pasteur filter, the, 1S4 

Pathogenic bacteria, 47 

Pepsin, action of, 207 

Percolation of ground-water, 145 

Perflation, 102 

Permissible impurity in air, 95 

in the soil, 144 
Peroxide of hydrogen, 309 
Personal disinfection, 317 

hygiene, 251 
Petri dish, 40 
Pettenkofer'stest for carbonic acid, 

404 
Phagocytosis, theory of, 54 
Phosphates in water, 196 

test for, 412 
Physical examination of water, 190 
Physiology of digestion, the, 203 
Plenum system, 131 
Plumbing for sewage, 343 
Pneumatic sewerage system, 339 
Poisson's formula, 390 
Pollution of well-water, 146, 150 



432 



INDEX. 



Population, actual increment of, 
393 

daily, 396 

estimation of, 393 

natural increment of, 393 

weekly, 396 
Pork, 230 

Portable steam radiator, 118 
Post-hospitals, 373 
Postulates of Koch, 51 
Predisposing conditions, 30 
Preparation of culture media, 42 
Preservatives, use of, in foods, 240 
Prismatic devices, increased light- 
ing by, 279 
Probable duration of life, 399 
Probation, camps of, 334 
Products of combustion, 74 
Prophylaxis, 30 
Proteid food, functions of, 213 

sources of, 214 
Ptomaines, 47 
Ptyalin, action of, 205 
Pumping, effect of excessive, 147 
Purification of air by fire, 93 

of river-water, 140 

of sewage, 364 

of subsoil or ground-water, 143 

of water, 158 

by chemical treatment, 163 
by filtration, 166 
by subsidence, 161 
domestic, 176 
Purity of air in hospitals, 97 

of ground-water, 145 



QUARANTINE, 320 
at Canadian and Mexican ports, 
333 
conditions requiring, 325 
house, 335 
inland, 333 
laws, purpose of, 322 
local, 335 
origin of, 320 
original meaning of, 321 
railroad, 335 

regulations at ports of departure, 
322 
of entry, 325 



Quarantine regulations during voy- 
age, 324 
school, 293 
stations, location of, 328 

requisites for, 328 
treatment of cargoes in, 329 
of passengers in, 329, 332 
of vessels in, 329-331 
Quarantines, inspection of, 333 



RADIANT heat, 113 
Radiating surface, estimation 
of, 131 
Radiation, direct, 128 
direct-indirect, 129 
indirect, 128 
Railroad quarantine, 335 
Rainfall, amount of, per acre, 137 
-water, 136 
cisterns, 138 
conductors, 347 
filtration of, 138 
softness of, 139 
Rations, army, 380 
Recruits, qualifications of, 370 
Refuge, camps of, 334 
Registers, size of, 125 
Registration records, importance 
. of, 395 

Relative value of foods, 241 
Removal of sewage, 337 
Respiration impurities, effects of, 69 
Respiratory vitiation, diseases due 

to, 86 
River- water, 140 

self-purification of, 140 
Roasting and broiling, 233 
Rooms, final disinfection of, 318 
Rubber, 273 



Q ALICYL ATES, test for, in milk, 

O 419 

Salicylic acid, test for, in milk, 

419 
Saliva, functions of the, 206 
Salivary digestion, 205 
Salts, food-, functions of, 218 

sources of 219 
Sand-filters, 167-176 



INDEX. 



433 



Sanitary cordon, the, 334 
Sanitation, 30 

Saprophytes, functions of, 46 
Schering's lamps, 314 

method of disinfection, 313 
Schizomycetes, 33 
School children, headache in, 285 
nervous diseases in, 285 
prevention of infection of, 293 
spinal deformities in, 286 
vaccination of, 296 
furniture, arrangement of, 2S8 

influence of, 286 
-houses, care of, 292 
cloak-rooms in, 290 
construction of, 289 
disinfection of, 290, 294 
location of, 290 
ventilation of, 289 
warming of, 289 
water-supply of, 292 
hygiene, 281 
infirmaries 296 
pathology, 282 
quarantine, 293 
rooms, lighting of, 289 
work, duration of, 282 
Schools, contagious diseases in, 297 
Sea-bathing, 267 
Sedimentation, 161 
Septicaemia, 52 

" Septic-tank" system of sewage 
treatment, 367 
advantages of, 368 
Sewage, chemical treatment of, 364 
composition of, 338 
filtration of, 364 
intermittent filtration of, 365 
pail system of removal, 341 
-plumbing, 342 

requirements of, 343 
-pollution of water, 140, 141 
purification of, 364 
removal of, 337 
the ultimate disposal of, 364 
treatment by electricity, 368 
by irrigation, 366 
by sub-irrigation, 366 
by the "septic-tank" system, 
367 
water-carriage of, 339, 341 



Sewerage, ejector system, 339 

pneumatic system, 339 

Shone system, 339 
Sewer-gas, 78 

bacteria in, 78 

composition of, 78 

influence of, on health, 90 
Sewers, 359 

advantages of "separate," 361 

"combined," 359 

construction of, 363 

"separate," 361 

shape of "combined," 360 

specifications for "separate," 362 

ventilation of, 361, 363 
Shallow wells, 145 
Shone sewage system, 339 
Sick-room, care of the, 317 

disinfection of the, 318 
Silk in clothing, 272 
Size of ventilation inlets, 109 
Smead system of ventilation, 107, 

290 
Soda, chlorinated, 306 
Soil air, 78 

circulation of, 80 
composition of, 79 
influence of, on health, 90 

bacteria in the, 79 

-pipe, the, 344 

connection of, with house- 
drain, 346 
location and construction of, 

344 
testing of, 351 
ventilation of, 343 

the, 79 
Soldier, clothing of the, 381 

instruction of the, in hygiene, 
385 

the food of the, 379 

work of the, 387 
Soldiers, weights carried by, 382 
Solids, total, in water, 193 
Soups and broths, 233 
Source of air-supply, 99 
Sources of water-supply, 136 
Spinal deformities in school chil- 
dren, 286 
Spirilla, 37 
Spores, characteristics of, 36, 38 



28 



434 



INDEX. 



Spores, formation of, 35-36 

Springs, 136 

Statistical inquiry, principles of, 

389 
Steam, disinfection by, 302 

-heating, 128 
Steapsin, action of, 209 
Sterilization, fractional, 41 

methods of, 41 

of apparatus, 41 
Sterilized milk, 223 
Sterilizer, the Forbes, 177 
Sterilizers, 42 
Stimulants, 242 

cautions in use of, 246 

classification of, 242 

function of, 242 

indications for use of, 242 
Stoves, 116 

gas-, 118 

objections to, 117 

oil-, 120 
Studies, order of, 283 
Sub-irrigation, 366 
Subsidence, water purification by, 

161 
Subsoil-water, 136, 142 
Sulphate of iron, 309 
Sulphur dioxide, 310 

fumigation with, 319 
Sulphuretted hydrogen, 90 
Sulphurous acid gas, 90, 310 
Surface-water, 136, 140 



TEA, 243 
and coffee, abuse of, 244 
Tests of well-water, 150 
The soil, limit of permissible im- 
purity in, 144 
purifying action of, 143 
Theory of antitoxins, 55 
of Buchner, 54 
of Chauveau, 54 
of Metchnikoff, 54 
of Pasteur, 54 
of phagocytosis, 54 
Total solids in water, 193 
Toxaemia, 52 
Toxins, 47 
Training, aim of physical, 265 



Transmission of, 126 
Trap, bell, 349 
Bower's, 350 
Cudell's, 349 

McClellan's anti-siphoning, 350 
S or siphon, 349 
sink or pot, 350 
Traps, 348 

seal of, 348, 349 
siphoning of, 350 
vent-pipes for, 351 
Tricresol, 308 
Trillat's method of disinfection, 

312 
Trypsin, action of, 208 
Typhoid fever and malaria, 377 
as an index of water purity, 

_ 159-161 _ 
dissemination of, 375 
due to flies, 376 
in camps, 375 

incubation period of, 375, 378 
Tyrotoxicon, 224 



VACCINATION of school chil- 
V dren, 296 
Variety in food, necessity for, 202, 

220 
Vegetables, cooking of, 237, 238 
Velocity of air-currents, 103 
Ventilating grates, 115, 116 
Ventilation and heating, 92 

artificial, 100, 110 

definition of, 93 

devices for, 105 

external, 92 

factors of, 94 

fans, 111, 112 

forces of, 100 

internal, 93 

natural, 100 

of school-houses, 289 

of sewers, 361, 363 

of soil-pipes, 343 

of water-closets, 318 

or vent-pipes, 351 

problems, formula for, 97 

Smead system of, 107 
Ventilators, 102 
Vital resistance, value of, 31 



__ 



INDEX. 



435 



Vital statistics, 388 
grouping in, 390 
methods of obtaining, 389 
numerical standard in, 390 

units in, 389 
probable error in, 391 
value of, 388 

of series in, 392 
variation in, 390 



WAKMED air, humidity of, 120, 
130 
Warming of school- houses, 289 
Washstands, overflow of, 353 
Waste-pipes, 343 

connection of, to house-fixtures, 
347 
with soil-pipes, 347 
Water, 132 

ammonia in, 194, 412 
bacterial examination of, 191 
bottle for collecting samples of, 

407 
-carriage of sewage, 339, 341 
chemical examination of, 193, 
406 
treatment of, 163, 177 
chlorine in, 193, 406 
classification of, 151, 197 
-closets, connection of, to water- 
supply, 357 
disinfection of, 359 
hopper, 356 
location of, 359 
pan, 354 

plug or plunger, 355, 356 
requisites for, 353 
siphon, 357, 358 
valve, 354, 355 
ventilation of, 358 
wash out, 357 
cost of sickness due to polluted 

water, 160 
deep- or artesian-, 136, 148 
diseases caused by impurities in, 

152-158 
double supply of, 134 
effects of impure, 159 
examination of, 406 
excretion of, 262 



Water, ground- or subsoil-, 136, 
142 

hardness of, 139, 196, 410 

lake-, 142 

lead in, 154, 196 

level of subsoil-, 144 

meters, 135 

nitrates in, 195, 408 

nitrites in, 195, 409 

organic matters in, 195 

percolation of, 145 

phosphates in, 196 

physical examination of, 190 

purification of, in the household, 
176 

-purity, index of, 159-161 

purity of subsoil-, 145 

quantity of, necessary, 132 

rain-, 136 

river-, 140 

sewage pollution of, 140, 141 

sources of, 136 

storage of, 162 

-supply of cities, 133 
of camps, 379 
of school houses, 292 • 

surface-, 136, 140 

tests for physical properties, 190, 
406 

the examination of, 189, 406 

the purification of, 140, 143, 158 

total solids in, 193 
Weights carried by soldiers, 382 
Well-water, pollution of, 146, 150 

testing of, 150 
Wells, construction and care of, 
149 

deep or artesian, 148 

location of, 150 

shallow, 145 
Welsbach light, the, 77 
Wheat, 235 

bread, characteristics of, 423 

-flour, 236 

characteristics of, 422 
Winds, 100 
Wool in clothing, 271 



7 INC chloride, 308 
Ll Zooglea, 37 



CATALOGUE OF PUBLICATIONS OF 

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706, 708 & 710 Sansom St., Philadelphia. 
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INDEX. 

ANATOMY^ Gray, p. 11 ; Treves, 30 ; Gerrish, 11; Brockway, 4. 

DICTIONAmES. Dunglison, p. 9 ; Duane, 8 ; National, 4. 

PHYSICS. Draper, p. 8 ; Martin & Rockwell, 19. 

PHYSIOLOGY". Foster, p. 10; Chapman, 5; Schofield, 25; Collins 
& Rockwell, 6 ; Hare, 12. [Remsen, 24. 

CHEMISTRY. Simon, p. 25 ; Attfield, 3 ; Martin & Rockwell, 19; 

PHARMACOLOGY. Cushny, p. 6. 

PHARMACY. Caspari, p. 5. 

MATERIA MEDICA. Culbretb, p. 7 ; Maisch, 19 ; Farquharson, 9 ; 

DISPENSATORY. National, p. 20. [Bruce, 4 : Schleif, 24. 

THERAPEUTICS. Hare, p. 13 ; Fothergill, 10 ; Whitla, 31 ; Hayem 
& Hare, 14 ; Bruce, 4 ; Schleif, 24 ; Cushny, 7 ; Tirard, 29. 

PRACTICE. Flint, p. 10 ; Loomis & Thompson, 18 ; Malsbary, 19 ; 
Thompson, 29. 

DIAGNOSIS. Musser, p. 20; Hare, 13; Simon, 25; Herrick, 14; Hutchi- 
son & Rainey, 15 ; Collins, 6. 

CLIMATOLOGY. Solly, p. 26 ; Hayem & HaTe, 14. 

NERVOUS DISEASES. Dercum, p. 8 ; Potts, 23. 

MENTAL DISEASES. Clouston, p. 6 ; Folsom, 10. 

BACTERIOLOGY. Abbott, p. 2 ; Vaughan & Novy, 30 ; Senn's 
(Surgical), 25. Park, 22 ; Coates, 6. [Vale, 21. 

HISTOLOGY. Klein, p. 17 ; Schafer, 24 ; Dunham, 8 ; Nichols & 

PATHOLOGY. Green, p. 12; Gibbes, 11; Coats, 6; Nichols & Vale, 21. 

SURGERY. Park, p. 22; Dennis, 8; Roberts, 24; Ashhurst, 3; Treves, 29; 
Cheyne & Burghard, 5 ; Gallaudet, 11. 

SURGERY— OPERATIVE. Stimson, p. 27 ; Smith, 26 ; Treves, 29. 

SURGERY— ORTHOPEDIC. Young, p. 31. 

SURGERY— MINOR. Wharton, p. 30. TWippern & 

FRACTURES and DISLOCATIONS. Stimson, p. 27. [BalleDger,31 

OPHTH ALMOLOGY. Norris & Oliver, p. 21 ; Nettleship, 21 ; Juler, 17; 

OTOLOGY. Politzer, p. 23; Burnett, 5; Field. 10; Bacon, 3. 

LARYNGOLOGY and RHINOLOGY. Coakley, p. 6 ; 

DENTISTRY. Essig (Prosthetic), p. 9 ; Kirk (Operative), 17 ; Ameri- 
can System. 2 ; Coleman, 6; Burchard. 4. 

URINARY DISEASES. Roberts, p. 24 ; Black, 4. 

VENEREAL DISEASES. Taylor, p. 28 ; Hayden, 14 ; Cornil, 6 ; 

SEXUAL DISORDERS. Fuller, p. 11 ; Taylor, 28. 

DERMATOLOGY. Hyde, p. 16; Jackson, 16; Pye-Smith, 23; Mor- 
ris, 20 ; Jamieson, 16 ; Hardaway, 12 ; Grindon, 12. 

GYNECOLOGY. American System, p. 3 ; Thomas & Munde\ 29 
Emmet, 9 ; Davenport, 7 ; May, 19 ; Dudley, 8 ; Crockett, 7. 

OBSTETRICS. American System, p. 3 ; Davis, 7 ; Parvin, 22 ; Play- 
fair. 22 ; King, 17 ; Jewett, 16 ; Evans, 9. 

PEDIATRICS. Smith, p. 26 ; Thomson, 29 ; Williams, 31 ; Tuttle, 30. 

HYGIENE. Egbert, p. 9 ; Richardson, 24 ; Coates, 6. 

MEDICAL JURISPRUDENCE. Taylor, p. 28. 

QUIZ SERIES, POCKET TEXT-BOOKS and MANUALS. 
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ABBOTT (A. C). PRINCIPLES OF BACTERIOLOGY: a Practical 
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with 109 engrav., of which 26 are colored. Cloth, $2.75, net. 



cessfully. To those who require a 
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One of its most attractive charac- 
teristics is that the directions are so 
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AMERICAN SYSTEM OF PRACTICAL MEDICINE. A SYS- 
TEM OF PRACTICAL MEDICINE. In contributions by Various 
American Authors. Edited by Alfred L. Loomis, M.D., LL.D., 
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"The American Svstem of Medi- 



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AMERICAN SYSTEM OF DENTISTRY. In treatises by various 
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PROSTHETIC DENTISTRY. Edited by Charles J. Essig, M.D., 
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derstood as a part of civilization. — 
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It is a practical course on prosthetics 
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It is replete in every particular 
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AMERICAN TEXT-BOOK. OF ANATOMY. See Gerrish, page 1 1 . 

ALLEN (HARRISON). A SYSTEM OF HUMAN ANATOMY- 

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A PRACTICE OF OBSTETRICS BY AMERICAN AU- 
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A TREATISE ON SURGERY BY AMERICAN AUTHORS. 

FOB STUDENTS AND PBACTITIONEBS OF SUBGEBY AND 
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ASHHURST (JOHN, JR.). THE PBINCIPLES AND PBACTICE 

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As a masterly epitome of what has 
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ATTFIELD (JOHN). CHEMISTBY : GENEBAL, MEDICAL AND 
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scientific chemical nomenclature has I Medical Review. 

BARNES (ROBERT AND FANCOURT). A SYSTEM OF OB- 
STETBIC MEDICINE AND SUBGEBY. Octavo, 872 pages, with 
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BACON (GORHAM). ON THE EAB. One 12mo. volume, 400 pages, 
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BILLINGS (JOHN S.). THE NATIONAL MEDICAL DICTIONARY. 
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BLOXAM (C. L.). CHEMISTRY, INORGANIC AND ORGANIC. 
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BRUCE (J. MITCHELL). MATERIA MEDICA AND THERA- 



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BRYANT (THOMAS). THE PRACTICE OF SURGERY. Fourth 
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of 1040 pages, with 727 illustrations. Cloth, $6.50 ; leather, $7.50. 

BURCHARD (HENRY H.). DENTAL PATHOLOGY AND THER- 
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CARTER (R BRUDENELL) AND FROST (W. ADAMS). OPH- 
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CASPARI (CHARLES JR.). 

For Students and Pharmacists. 

680 pages, with 288 illustrations. 

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COAKL.EY (CORNELIUS G.). THE DIAGNOSIS AND TREAT- 
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COLEMAN (ALFRED). A MANUAL OF DENTAL SURGERY 
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practitioner with the advances in 
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Well written and up to date. It 
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CONDHE (D. FRANCIS). A PRACTICAL TREATISE ON THE DIS- 
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CORNDL. (V.). SYPHILIS: ITS MORBID ANATOMY, DIAGNO- 
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CROOK (JAMES K.) ON MINERAL WATERS OF THE 
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CULBRETH (DAVID M. R). MATERIA MEDICA AND PHAR- 
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CUSHNY (ARTHUR R.). TEXT-BOOK OF PHARMACOLOGY. 

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D ALTON (JOHN C). A TREATISE ON HUMAN PHYSIOLOGY. 

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DOCTRINES OF THE CIRCULATION OF THE BLOOD. In 



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DAVENPORT (F. H.). DISEASES OF WOMEN. A Manual of 

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knowing, and presents these princi- 
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DAVIS (EDWARD P.). A TREATISE ON OBSTETRICS. FOR 

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DE LA BECHE'S GEOLOGICAL OBSERVER. In one large octavo 
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DENNIS (FREDERIC S.) AND BDLL.INGS (JOHN S.). A SYS- 
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DERCUM (FRANCIS X., EDITOR). A TEXT-BOOK ON 
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DE SCHWEINITZ (GEORGE E.). THE TOXIC AMBLYOPIAS. 

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DRUITT (ROBERT). THE PRINCIPLES AND PRACTICE OF 
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DUANE (ALEXANDER). A DICTIONARY OF MEDICINE AND 
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eather, $4.00, net. 

DUDLEY (E. C). THE PRINCIPLES AND PRACTICE OF 
GYNECOLOGY. New (2d) edition. Handsome octavo of 717 pages, 
with 453 illustrations in black and colors, and 8 colored plates. Cloth, 
$5.00, net; leather, $6.00, net; half Morocco, $6.50, net. Just ready. 



tice of modern gynecology. — Inter- 
national Medical Magazine. 



The book can be safely recom- 
mended as a complete and reliable 
exposition of the principles and prac- 

DUNCAN (J. MATTHEWS). CLINICAL LECTURES ON THE 
DISEASES OF WOMEN. Delivered in St. Bartholomew's Hospital. 
In one octavo volume of 175 pages. Cloth, $1.50. 

DUNHAM (EDWARD K.). MORBID AND NORMAL HIS- 
TOLOGY. Octavo, 450 pages,with 363 illustrations. Cloth, $3.25, net. 
The best one-volume text or refer- 1 of published in America. — Virginia 
ence book on histology that we know 1 Medical Soni-Month/y. 

NORMAL HISTOLOGY. New (2d) edition. Octavo, 319 pages, 

with 244 illustrations. Just ready. Cloth, $2.50, net. 



Lea Beothees & Co., Philadelphia and New Yoek. 9 



DUNGLISON (ROBLEY). A DICTIONARY OF MEDICAL SCI- 
ENCE. Containing a full explanation of the various subjects and 
terms of Anatomy, Physiology, Medical Chemistry, Pharmacy, Phar- 
macology, Therapeutics, Medicine, Hygiene, Dietetics, Pathology, Sur- 
gery, Ophthalmology, Otology, Laryngology, Dermatology, Gynecol- 
ogy, Obstetrics, Pediatrics, Medical Jurisprudence, Dentistry, etc., etc. 
By Robley Dunglison, M. D., LL. D., late Professor of Institutes 
of Medicine in the Jefferson Medical College of Philadelphia. Edited 
by Richaed J. Dttnglison, A. M., M. D. Twenty-second edition, thor- 
oughly revised and greatly enlarged and improved, with the Pronuncia- 
tion, Accentuation and Derivation of the Terms. With Appendix. 
In one magnificent imperial octavo volume of about 1400 pages. 
Shortly. Notices of previous edition are appended. 



scarcely be measured. — Med. Record. 
Pronunciation is indicated by the 
phonetic system. The definitions are 
unusually clear and concise. The 
book is wholly satisfactory. — Uni- 
versity Medical Magazine. 



The most satisfactory and authori- 
tative guide to the derivation, defini- 
tion and pronunciation of medical 
terms.- — The CharlotteMed. Journal. 

Covering the entire field of medi- 
cine, surgery and the collateral 
sciences, its range of usefulness can 

EDES (ROBERT T.). TEXT-BOOK OF THERAPEUTICS AND 
MATERIA MEDICA. In one 8vo. volume of 544 pages. Cloth, $3.50 ; 
leather, $4.50. 

EDIS (ARTHUR W.). DISEASES OF WOMEN. A Manual for 
Students and Practitioners. In one handsome 8vo. volume of 576 pages, 
with 148 engravings. Cloth, $3 ; leather, $4. 

EGBERT (SENECA). A MANUAL OF HYGIENE AND SANI- 
TATION. In one 12mo. volume of 359 pages, with 63 illustrations. 
Cloth, Net, $2.25. 



It is written in plain language, 
and, while primarily designed for 
physicians, it can be studied with 
profit by any one of ordinary intel- 



ligence. The writer has adapted it 
to American conditions, and bis 
suggestions are, above all, practical. 

— The New York Medical Journal. 



ELLIS (GEORGE VINER). DEMONSTRATIONS IN ANATOMY. 

Eighth edition. Octavo, 716 pages, with 249 engravings. Cloth, 
$4.25 ; leather, $5.25. 

EMMET (THOMAS ADDIS). THE PRINCIPLES AND PRAC- 
TICE OF GYNECOLOGY. Third edition. Octavo, 880 pages, with 
150 original engravings. Cloth, $5 ; leather, $6. 

ERICHSEN (JOHN E.). THE SCIENCE AND ART OF SUR- 
GERY. Eighth edition. In two large octavo volumes containing 
2316 pages, with 984 engravings. Cloth, $9 ; leather, $11. 

ESSIG (CHARLES J.). PROSTHETIC DENTISTRY. See American 

Text-Books of Dentistry, page 2. 

EVANS (DAVID J.). A POCKET TEXT-BOOK OF OBSTETRICS. 
In one handsome 12mo. volume of about 300 pages, with many illustra- 
tions. Shortly. Lea's Series of Pocket Text-books, edited by Bern B. 
Gallaudet, M. D. See page 18. 

FARQUHARSON (ROBERT). A GUIDE TO THERAPEUTICS. 
Fourth American from fourth English edition, revised by Feank 
Woodbuey, M. D. In one 12mo. volume of 581 pages. Cloth, $2.50. 



10 Lea Brothers & Co., Philadelphia and New York. 

FIELD (GEORGE P.). A MANUAL OF DISEASES OF THE 
EAE. Fourth edition. In one octavo volume of 391 pages, with 73 
engravings and 21 colored plates. Cloth, $3.75. 

FLINT (AUSTIN). A TEEATISE ON THE PRINCIPLES AND 
PRACTICE OF MEDICINE. Seventh edition, thoroughly revised 
by Frederick P. Henry, M.D. In one large 8vo. volume of 1143 
pages, with engravings. Cloth, $5.00 ; leather, $6.00. 



The work has well earned its lead 
ing place in medical literature.— 
Medical Record. 



The best of American text-books 
on Practice. — Amer. Medico-Surgical 
Bulletin. 

- A MANUAL OF AUSCULTATION AND PERCUSSION ; of 
the Physical Diagnosis of Diseases of the Lungs and Heart, and of 
Thoracic Aneurism. Fifth edition, revised by James C. Wilson, M.D. 
In one handsome 12mo. volume of 274 pages, with 12 engravings. 

— A PRACTICAL TREATISE ON THE DIAGNOSIS AND 



TREATMENT OF DISEASES OF THE HEART. Second edition 
enlarged. In one octavo volume of 550 pages. Cloth, $4. 

ON PHTHISIS : ITS MORBID ANATOMY ETIOLOGY, ETC. 

A Series of Clinical Lectures. In one 8vo. volume of 442 pages. 
Cloth, $3.50. 

FOLSOM (C. F.). AN ABSTRACT OF STATUTES OF U. S. 
ON CUSTODY OF THE INSANE. In one 8vo. vol. of 108 pages. 
Cloth, $1.50. With Clouston on Mental Diseases (new edition, see 
page 6) $5.00, net, for the two works. 

FORMULARY, POCKET, see page 32. 

FOSTER (MICHAEL). A TEXT-BOOK OF PHYSIOLOGY. New 

(6th) and revised American from the sixth English edition. In one 
large octavo volume of 923 pages, with 257 illustrations. Cloth, $4.50 ; 
leather, $5.50. 



Unquestionably the best book that 
can be placed in the student's hands, 
and as a work of reference for the 
busy physician it can scarcely be 
excelled. — The Phila. Polyclinic. 



This single volume contains all 
that will be necessary in a college 
course, and all that the physician 
will need as well. — Dominion Med. 
Monthly. 



FOTHERGILL (J. MILNER). THE PRACTITIONER'S HAND- 
BOOK OF TREATMENT. Third edition. In one handsome octavo 
volume of 664 pages. Cloth, $3.75 ; leather, $4.75. 

FOWNES (GEORGE). A MANUAL OF ELEMENTARY CHEM- 
ISTRY (INORGANIC AND ORGANIC). Twelfth edition. Em- 
bodying Watts' Physical and Inorganic Chemistry. In one royal 
12mo. volume of 1061 pages, with 168 engravings, and 1 colored 
plate. Cloth, $2.75 ; leather, $3.25. 

FRANKLAND (E.) AND JAPP (F.R.). INORGANIC CHEMISTRY. 

In one handsome octavo volume of 677 pages, with 51 engravings and 
2 plates. Cloth, $3.75 ; leather, $4.75. 

FULLER (HENRY). ON DISEASES OF THE LUNGS AND AIR 

PASSAGES. Their Pathology, Physical Diagnosis, Symptoms and 
Treatment. From second English edition. In one 8vo. volume of 475 
pages. Cloth, $3.50. 



Lea Brothebs & Co., Philadelphia and New York. 11 



FULLER (EUGENE). DISORDERS OF THE SEXUAL OR- 
GANS IN THE MALE. In one very handsome octavo volume of 
238 pages, with 25 engravings and 8 full-page plates. Cloth, $2. 



It is an interesting work, and one 
which is timely and needed. — Medi- 
cal Fortnightly. 

The book is valuable and instruc- 
tive and brings views of sound 
GALLAUDET (BERN B.). A 



pathology and rational treatment to 
many cases of sexual disturbance 
whose treatment has been too often 
fruitless for good. — Annals of 
Surgery. 

POCKET TEXT-BOOK ON SUR- 
GERY. In one handsome 12mo. volume of about 400 pages, with many 
illustrations. Shortly. Lea's Series of Pocket Text-books, edited by 
Bern B. Gallatjdet, M. D. See page 17. 
GANT (FREDERICK JAMES). THE STUDENT'S SURGERY. A 
Multum in Parvo. In one square octavo volume of 845 pages, with 
159 engravings. Cloth, $3.75. 
GERRISH (FREDERIC H.). A TEXT-BOOK OF ANATOMY. 
By American Authors. Edited by Frederic H. Gerrish, M. D. In one 
imp. octavo volume of 915 pages, with 950 illustrations in black and 
colors. Cloth, $6.50; flexible waterproof, $7; leather, $7.50, net; 
half Morocco, $8.00, net. 



any similar text-book with which 
we are familiar. — The Boston Medi- 
cal and Surgical Journal. 

We believe that this volume not 
only takes rank with all other works 
on anatomy, but in some respects is 
superior to any now available. — The 
Chicago Medical Recorder. 

There is nothing with which to 
find fault, everything to praise. The 
work is the most remarkable and 
most valuable volume of the year. — 
Buffalo Medical Journal. 



The illustrations far outnumber 
and exceed in size and in profusion 
of colors those in any previous work ; 
and they can well claim to be the 
most successful series of anatomical 
pictures in the world. — The Ameri- 
can Practitioner and News. 

The chief merit in the book will 

be found in the descriptive text, 

which is accurate, concise, and gives 

the essentials of descriptive anatomy 

with less waste of words and better 

emphasis of important points than 

GD3BES (HENEAGE). PRACTICAL PATHOLOGY AND MORBID 
HISTOLOGY. Octavo, 314 pages, with 60 illustrations. Cloth, $2.75. 

GRAY (HENRY). ANATOMY, DESCRIPTIVE AND SURGICAL. 
New and thoroughly revised American edition, much enlarged in text, 
and in engravings in black and colors. In one imperial octavo volume 
of 1239 pages, with 772 large and elaborate engravings on wood. Price 
of edition with illustrations in colors : cloth, $7 ; leather, $8. Price 
of edition with illustrations in black : cloth, $6 ; leather, $7. 

This is the best single volume 
upon Anatomy in the English 
language. — University Medical Mag- 
azine. 

Gray's Anatomy affords the student 
more satisfaction than any other 
treatise with which we are familiar. 
— Buffalo Med. Journal. 

The most largely used anatomical 
text-book published in the English 
language. — Annals of Surgery. 

Particular stress is laid upon the 
practical side of anatomical teach- 



ing, and especially the Surgical 
Anatomy. — Chicago Med. Recorder. 

Holds first place in the esteem of 
both teachers and students. — The 
Brooklyn Medical Journal. 

The foremost of all medical text- 
books. — Medical Fortnightly. 

Gray's Anatomy should be the 
first work which a medical student 
should purchase, nor should he be 
without a copy throughout his pro- 
fessional career.— Pittsburg Medical 
Review. 



12 Lea Brothers & Co., Philadelphia and New York. 

GOULD (A. PEARCB). SURGICAL DIAGNOSIS. In one 12mo. 
vol. of 589 pages. Cloth, $2. See Student's Series of Manuals, p. 27. 

GREEN (T. HENRY). PATHOLOGY AND MORBID ANATOMY 

New (8th) American from the eighth London edition. In one hand- 
some octavo volume of 582 pages, with 216 engravings and a colored 
plate. Cloth, $2.50, net. 



A. work that is the text-book of 
probably four-fifths of all the stu- 
dents of pathology in the United 
States and Great Britain. — The 
American Practitioner and News. 



The work is an essential to the 
practitioner — whether as surgeon or 
physician. It is the best of up-to- 
date text-books. — Virginia Medical 
Monthly. 

GREENE (WILLIAM HO. A MANUAL OF MEDICAL CHEM- 
ISTRY. For the Use of Students. Based upon Bowman's Medical 
Chemistry. In one 12mo. vol. of 310 pages, with 74 illus. Cloth, $1.75. 

GROSS (SAMUEL. D.). A PRACTICAL TREATISE ON THE DIS- 
EASES, INJURIES AND MALFORMATIONS OF THE URINARY 
BLADDER, THE PROSTATE GLAND AND THE URETHRA. 
Third edition. Octavo, 574 pages, with 170 illustrations Cloth, $4.50. 

GRINDON (JOSEPH). A POCKET TEXT-BOOK OF SKIN 
DISEASES. In one handsome 12mo. volume of 350 pages, with 
many illustrations. Shortly. Lea's Series of Pocket Text-books, edited 
by Bern B. Gallaudet, M. D. See page 18. 

HABERSHON (S. O.). ON THE DISEASES OF THE ABDOMEN 
Second American from the third English edition. In one octavo vol- 
ume of 554 pages, with 11 engravings. Cloth, $3.50. 

HALL (WINFIELD S.). TEXT-BOOK OF PHYSIOLOGY. Octavo 
of 672 pages, with 343 engravings, and 6 full page colored plates. 
Cloth, $4.00 ; leather, $5.00, net. 



of 'which needs to be more strongly 
impressed upon students A book 
which makes this so easily possible 
is to be highly commended. — West- 
em Medical Revieiv. 



Truly a scientific treatment of the 
subject. The clearness with which 
physiological facts are demonstrated 
makes it of special value to the 
medical student. The science of 
physiology is one, the importance 

HAMILTON (ALLAN MCLANE). NERVOUS DISEASES, THEIR 
DESCRIPTION AND TREATMENT. Second and revised edition. 
In one octavo volume of 598 pages, with 72 engravings. Cloth, $4. 

HARD AW AY (W. A.). MANUAL OF SKIN DISEASES. New (2d) 
edition. In one 12mo. volume of 560 pages, with 40 illustrations and 
2 plates. Cloth, $2.25, net. 



day clinical experience. His great 
strength is in diagnosis, descriptions 
of lesions and especially in treat- 
ment. — Indiana 3Iedical Journal. 



The best of all the small books to 
recommend to students and practi- 
tioners. Probably no one of our 
dermatologists has had a wider every- 

HARE (HOBART AMORY) ON THE MEDICAL COMPLICA- 
TIONS AND SEQUELJE OF TYPHOID FEVER. Octavo, 276 
pages, 21 engravings and two full-page plates. Cloth, $2.40, net. 
A very valuable production. One I read with great profit. — Cleveland 

of the very best products of Dr. Journal of Medicine. 

Hare and one that every man can I 



Lea Brothers & Co., Philadelphia and New York. 13 



HARE (HOBART AMORY). PRACTICAL DIAGNOSIS. THE 
USE OF SYMPTOMS IN THE DIAGNOSIS OF DISEASE. New 
(4th) edition. In one octavo volume of 623 pages, with 205 engravings 
and 14 full-page colored plates. Cloth, $5.00, net; half Morocco, 

£6.50, net. 



It is unique in many respects, and 
the author has introduced radical 
changes which will be welcomed by 
all. Anyone who reads this book 
will become a more acute observer, 
will pay more attention to the simple 
yet indicative signs of disease, and 



he will become a better diagnosti- 
cian. This is a companion to Prac- 
tical Therapeutics, by the same 
author, and it is difficult to conceive 
of any two works of greater practical 
utility. — Medical Review. 



HARE (HOBART AMORY). A TEXT-BOOK OF PRACTICAL 
THERAPEUTICS, with Special Reference to the Application of Reme- 
dial Measures to Disease and their Employment upon a Rational 
Basis. With articles on various subjects by well-known specialists. 
New (8th) and revised edition. In one octavo volume of 796 pages, 
with 37 engravings and 3 colored plates. Cloth, $4.00, net ; leather, 
$5.00, net; half Morocco, $5.50, act. Just ready. 



Its classifications are inimitable, 
and the readiness with which any- 
thing can be found is the most won- 
derful achievement of the art of in- 
dexing. This edition takes in all 
the latest discovered remedies. — 
The St. Louis Clinique. 

The great value of the work lies 
in the fact that precise indications 
for administration are given. A 
complete index of diseases and 
remedies makes it an easy reference 
work. It has been arranged so that 



it can be readily used in connection 
with Hare's Practical Diagnosis. 
For the needs of the student and 
general practitioner it has no equal. 
— Medical Sentinel. 

The best planned therapeutic work 
of the century. — American Prac- 
titioner and Nexcs. 

It is a book precisely adapted to 
the needs of the busy practitioner, 
who can rely upon finding exactly 
what he needs. — The National Med- 
ical Review. 



HARE (HOBART AMORY, EDITOR). A SYSTEM OF PRAC- 
TICAL THERAPEUTICS. In a series of contributions by eminent 
practitioners. In four large octavo volumes comprising about 4500 
pages, with about 550 engravings. Vol. IV., now ready. For sale by sub- 
scription only. Full prospectus free on application to the Publishers. 
Regular price, Vol. IV., cloth, $6 ; leather, $7 ; half Russia, $8. 
Price Vol. IV. to former or new subscribers to complete work, cloth, 
$5 ; leather, $6 ; half Russia, $7. Complete work, cloth, $20; leather, 
$24 ; half Russia, $28. 

The great value of Hare's System of Practical Therapeutics has led to a 
widespread demand for a new volume to represent advances in treatment 
made since the publication of the first three. More than fulfilling this 
request the Editor has secured contributions from practically a new corps 
ot equally eminent authors, so that entirely fresh and original matter is 
ensured. The plan of the work, which proved so successful, has been fol- 
lowed in this new volume, which will be found to present the latest devel- 
opments and applications of this most practical branch of the medical art. 
The entire System is an unrivalled encyclopaedia on the practical parts of 
medicine, and merits the great success it has won for that reason. 



14 Lea Brothers & Co., Philadelphia and New York. 



HARTSHORNE (HENRY). ESSENTIALS OF THE PRINCIPLES 
AND PRACTICE OF MEDICINE. Fifth edition. In one 12mo. 
volume, 669 pages, with 144 engravings. Cloth, $2.75 . 



— A HANDBOOK OF ANATOMY AND PHYSIOLOGY. In one 

12mo. volume of 310 pages, with 220 engravings. Cloth, $1.75. 



— A CONSPECTUS OF THE MEDICAL SCIENCES. Comprising 
Manuals of Anatomy, Physiology, Chemistry, Materia Medica, Prac- 
tice of Medicine, Surgery and Obstetrics. Second edition. In one royal 
12mo. vol. of 1028 pages, with 477 illus. Cloth, $4.25 ; leather, $5. 



HAYDEN (JAMES R.). A MANUAL OF VENEREAL DISEASES. 

New (2d) edition. In one 12mo. volume of 304 pages, with 54 en- 
gravings. Cloth, $1.50, net. 



It is practical, concise, definite 
and of sufficient fulness to be satis- 
factory. — Chicago Clinical Review. 



It is well written, up to date, and 
will be found very useful. — Inter- 
national Medical Magazine. 



HAYEM (GEORGES) AND HARE (H. A.). PHYSICAL AND 
NATURAL THERAPEUTICS. The Remedial Use of Heat, Elec- 
tricity, Modifications of Atmospheric Pressure, Climates and Mineral 
Waters. Edited by Prof. H. A. Hare, M. D. In one octavo volume 
of 414 pages,with 113 engravings. Cloth, $3. 



This well-timed volume is particu- 
larly adapted to the requirements 
of the general practitioner. The 
section on mineral waters is most 
scientific and practical. Some 200 
pages are given up to electricity and 
evidently embody the latest scien- 



tific information on the subject. 
Altogether this work is the clearest 
and most practical aid to the study 
of nature's therapeutics that has yet 
come under our observation. — The 
Medical Fortnightly. 



HERMAN (G. ERNEST). FIRST LINES IN MIDWIFERY. In 
one 12mo. vol. of 198 pages, with 80 engravings. Cloth, $1.25. See 
Student's Series of Manuals, page 27. 

HERMANN (L.). EXPERIMENTAL PHARMACOLOGY. A Hand- 
book of the Methods for Determining the Physiological Actions of 
Drugs. Translated by Robert Meade Smith, M. D. In one 12mo. 
volume of 199 pages, with 32 engravings. Cloth, $1.50. 

HERRICK (JAMES B.). A HANDBOOK OF DIAGNOSIS. In 

one handsome 12mo. volume of 429 pages, with 80 engravings and 2 
colored plates. Cloth, $2.50. 

We commend the book not only to Excellently arranged, practical, 

the undergraduate, but also to the concise, up-to-date, and eminently 

physician who desires a ready means well fitted for the use of the prac- 

of refreshing his knowledge of diag- titioner as well as of the student. — 

nosis in the exigencies of professional Chicago Med. Recorder. 
life. — Memphis Medical Monthly. 



HILL. (BERKELEY). SYPHILIS AND LOCAL CONTAGIOUS 
DISORDERS. In one 8vo. volume of 479 pages. Cloth, $3.25. 



Lea Brothers & Co., Philadelphia and New York. 15 

HILIilER (THOMAS). A HANDBOOK OF SKIN DISEASES. 
Second edition. In one royal 12mo. volume of 353 pages, with two 
plates. Cloth, $2.25. 

HIRST (BARTON C.) AND PEERSOL. (GEORGE A.). HUMAN 

MONSTROSITIES. Magnificent folio, containing 220 pages of text 
and illustrated with 123 engravings and 39 large photographic plates 
from nature. In four parts, price each, $5. Limited edition. For sale 
by subscription only. 

HOBLYN (RICHARD D.). A DICTIONARY OF THE TERMS 
USED IN MEDICINE AND THE COLLATERAL SCIENCES. 
New (13th) edition. In one 12mo. volume of 845 pages. Cloth, 
$3.00, net. Just ready. 

HODGE (HUGH L..). ON DISEASES PECULIAR TO WOMEN, 
INCLUDING DISPLACEMENTS OF THE UTERUS. Second and 
revised edition. In one 8vo. vol. of 519 pp., with illus. Cloth, $4.50. 

HOFFMANN (FREDERICK) AND POWER (FREDERICK B.). 

A MANUAL OF CHEMICAL ANALYSIS, as Applied to the 
Examination of Medicinal Chemicals and their Preparations. Third 
edition, entirely rewritten and much enlarged. In one handsome octavo 
volume of 621 pages, with 179 engravings. Cloth, $4.25. 

HOLMES (TIMOTHY). A TREATISE ON SURGERY. Its Prin- 
ciples and Practice. A new American from the fifth English edition. 
Edited by T. Pickering Pick, F.R.C.S. In one handsome octavo vol- 
ume of 1008 pages, with 428 engravings. Cloth, $6 ; leather, $7. 

A SYSTEM OF SURGERY. With notes and additions by various 



American authors. Edited by John H. Packard, M. D. In three 
very handsome 8vo. volumes containing 3137 double-columned pages, 
with 979 engravings and 13 lithographic plates. Per volume, clotn, $6 ; 
leather, $7 ; half Russia, $7.50. For sale by subscription only. 

HORNER (WILLIAM E.). SPECIAL ANATOMY AND HIS- 
TOLOGY. Eighth edition, revised and modified. In two large 8vo. 
volumes of 1007 pages, containing 320 engravings. Cloth, $6. 

HUDSON (A.). LECTURES ON THE STUDY OF FEVER. In one 
octavo volume of 308 pages. Cloth, $2.50. 

HUTCHISON (ROBERT) AND RAINY (HARRY). CLINICAL 
METHODS. A GUIDE TO THE PRACTICAL STUDY OF 
MEDICINE. In one 12mo. volume of 562 pages, with 137 engrav- 
ings and 8 colored plates. Cloth, $3.00. 



A comprehensive, clear and re- 
markably up-to-date guide to clinical 
diagnosis. The illustrations are 



plentiful and excellent. — Montreal 
Medical Journal. 



16 Lea Brothers & Co., Philadelphia and New York. 



HYDE (JAMES NEVINS). A PRACTICAL TREATISE ON DIS- 
EASES OF THE SKIN. New (5th) edition, thoroughly revised. 
Octavo, 866 pages, with 111 engravings and 24 full-page plates, 8 of 
which are colored. Just ready. Cloth, $4.50, net; leather, $5.50, net ; 
half Morocco, $6.00, net. 



This edition has been carefully re- 
vised, and every real advance has 
been recognized. The work answers 
the needs of the general practitioner, 
the specialist, and the student. — The 
Ohio Med. Jour. 

A treatise of exceptional merit 
characterized by conscientious care 
and scientific accuracy. — Buffalo 
Med. Journal. 

A complete exposition of our 
knowledge of cutaneous medicine as 
it exists to-day. The teaching in- 



culcated throughout is sound as well 
as practical. — The American Jour- 
nal of the Medical Sciences. 

It is the best one-volume work 
that we know. — Virginia Medical 
Semi-Monthly. 

A full and thoroughly modern 
text-book on dermatology. — The 
Pittsburg Medical Review. 

The most practical handbook on 
dermatology with which we are ac- 
quainted. — Chicago Medical Re- 
corder. 



JACKSON (GEORGE THOMAS). THE READY-REFERENCE 
HANDBOOK OF DISEASES OF THE SKIN. New (3d) edition. 
In one 12mo. volume of 637 pages, with 75 illustrations and a colored 
plate. Cloth, $2.50, net. 



As a student's manual, it may be 
considered beyond criticism. The 
book is singularly full. — St. Louis 
3fedical and Surgical Journal. 



Without doubt forms one of the 
best guides for the beginner in der- 
matology that is to be found in the 
English language. — Medicine. 



JAMIESON (W. ALLAN). DISEASES OF THE SKIN. Third 
edition. In one octavo volume of 656 pages, with 1 engraving and 9 
double-page chromo-lithographic plates. Cloth, $6. 



JEWETT (CHARLES). ESSENTIALS OF OBSTETRICS. In one 
12mo. volume of 356 pages, with 80 engravings and 3 colored plates. 
Cloth, $2.25. 



An exceedingly useful manual for 
student and practitioner. The au- 
thor has succeeded unusually well 
in condensing the text and in arrang- 



ing it in attractive and easily tangi- 
ble form. The book is well illus- 
trated throughout. — Nashville Jour, 
of Medicine and Surgery. 



THE PRACTICE OF OBSTETRICS. By American Authors. 

One large octavo volume of 763 pages, with 441 engravings in black 

and colors, and 22 full-page colored plates. Cloth, $5.00, net; 

leather, $6.00, net; half Morocco, $6.50, net. 

A clear and practical treatise upon the book abounds. The work is 

obstetrics by well-known teachers of sure to be popular with medical 

the subject. A special feature of students, as well as being of extreme 

this work would seem to be the value to the practitioner. — The 

excellent illustrations with which Medical Age. 



JONES (C. HANDF1ELD). CLINICAL OBSERVATIONS ON 
FUNCTIONAL NERVOUS DISORDERS. Second American edi- 
tion. In'one octavo volume of 340 pages. Cloth, $3.25. 



Lea Brothers & Co., Philadelphia and New York. 17 

JTJIjER (HENRY). A HANDBOOK OF OPHTHALMIC SCIENCE 
AND PRACTICE. Seoond edition. In one octavo volume of 549 
pages, with 201 engravings, 17 chromo-lithographic plates, test-types of 
Jaeger and Snellen, and Holmgren's Color-Blindness Test. Cloth, 
$5.50 ; leather, $6.50. 

The volume is particularly rich in | color blindness, etc. The sections 
matter of practical value, such as | devoted to treatment are singularly 
directions for diagnosing, use of full and concise. — Medical Age. 
instruments, testing for glasses, for | 

KING (A. F. A.). A MANUAL OF OBSTETRICS. New (8th) edition. 
In one 12mo. volume of 612 pages, with 264 illustrations. Cloth, 
$2.50, net. Just ready. 



From first to finish it is thoroughly 
practical, concise in expression, well 
illustrated, and includes a statement 
of nearly every fact of importance 
discussed in obstetric treatises or 



cyclopedias. The well-arranged 
index renders the book useful to 
the practitioner who is in haste to 
refresh his memory. — Virginia 
Medical Semi- Monthly. 

KIRK (EDWARD C). OPERATIVE DENTISTRY. Handsome 
octavo of 700 pages, with 751 illustrations. See American Text-Books 
of Dentistry, page 2. 



tempted. We can heartily recom- 
mend it to the profession. — The 
Ohio Dental Journal. 



We have only the highest praise 
for this valuable work. It is replete 
in every particular, and surpasses 
anything of the kind heretofore at- 

KL.EIN (E.). ELEMENTS OF HISTOLOGY. New (5th) edition. In 
one 12mo. volume of 506 pages, with 296 engravings. Cloth, $2.00, 
net. See Student's Series of Manuals, page 27. 



This work deservedly occupies a 
first place as a text-book on his- 
tology. — Canadian Practitioner. 



It is the most complete and con- 
cise work of the kind that has yet 
emanated from the press. — The Med- 
ical Age. 

LANDIS (HENRY G.). THE MANAGEMENT OF LABOR. In one 

handsome 12mo. volume of 329 pages, with 28 illus. Cloth, $1.75. 

LAURENCE (J. Z.) AND MOON (ROBERT C). A HANDY- 
BOOK OF OPHTHALMIC SURGERY. Second edition. In one 
octavo volume of 227 pages, with 66 engravings. Cloth, $2.75. 

LEA'S SERIES OF POCKET TEXT-BOOKS, edited by Bern 
B. Gallaudet, M. D. Covering the entire field of Medicine in a 
series of 16 very handsome 12mo. volumes of 350-450 pages each, 
profusely illustrated. Compendious, clear, trustworthy and modern. 
The following volumes constitute the series. 

Coates' Bacteriology and Hygiene. Brockway's Anatomy. Collins 
and Rockwell's Physiology. Martin and Rockwell's Chemistry 
and Physics. Nichols and Vale's Histology and Pathology. 
SCHLEIF'S Materia Medica, Therapeutics, Medical Latin, etc. Mals- 
bary's Practice of Medicine. Collins' Diagnosis. Potts' Nervous 
and Mental Diseases. Gallaitdet's Surgery. Grindon's Der- 
matology. Wippern and Ballenger'S Diseases of the Eye, Ear, 
Throat and Nose. Evans' Obstetrics. Crockett's Gynecology. 
Tuttle's Diseases of Children. 

For separate notices see under various authors' names. 






18 Lea Brothers & Co., Philadelphia and New York. 

LiEA (HENRY C). A HISTORY OF AURICULAR CONFESSION 
AND INDULGENCES IN THE LATIN CHURCH. In three 
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CHAPTERS FROM THE RELIGIOUS HISTORY OF SPAIN ; 

CENSORSHIP OF THE PRESS; MYSTICS AND ILLUMIN ATI - 
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BRIANDA DE BARDAXI. 12mo., 522 pages. Cloth, $2.50. 

FORMULARY OF THE PAPAL PENITENTIARY. In one 

octavo volume of 221 pages, with frontispiece. Cloth, $2.50. 

SUPERSTITION AND FORCE ; ESSAYS ON THE WAGER 

OF LAW, THE WAGER OF BATTLE, THE ORDEAL AND 
TORTURE. Fourth edition, thoroughly revised. In one hand- 
some royal 12mo. volume of 629 pages. Cloth, $2.75. 

STUDIES IN CHURCH HISTORY. The Rise of the Temporal 

Power — Benefit of Clergy — Excommunication. New edition. In one 
handsome 12mo. volume of 605 pages. Cloth, $2.50. 

AN HISTORICAL SKETCH OF SACERDOTAL CELIBACY 



IN THE CHRISTIAN CHURCH. Second edition. In one hand- 
some octavo volume of 685 pages. Cloth, $4.50. 

LOOMIS (ALFRED L.) AND THOMPSON (W. GILMAN, 
EDITORS). A SYSTEM OF PRACTICAL MEDICINE. In 
Contributions by Various American Authors. In four very hand- 
some octavo volumes of about 900 pages each, fully illustrated in 
in black and colors. Complete work now. ready. Per volume, cloth, 
$5; leather, $6 ; half Morocco, $7. For sale by subscription only. 
Full prospectus free on application to the Publishers. See American 
System of Practical Medicine, page 2. 

LYMAN (HENRY M.). THE PRACTICE OF MEDICINE. In one 
very handsome octavo volume of 925 pages, with 170 engravings. 
Cloth, $4.75 ; leather, $5.75. 



Complete, concise, fully abreast of 
the times and needed by all students 
and practitioners. — Univ. Med. Mag. 



An exceedingly valuable text-book. 
Practical, systematic, and well bal- 
anced. — Chicago Med. Recorder. 



LYONS (ROBERT D.). A TREATISE ON FEVER. In one octavo 
volume of 362 pages. Cloth, $2.25. 

MACKENZIE (JOHN NOLAND). ON THE NOSE AND THROAT. 

Handsome octavo, about 600 pages, richly illustrated. Preparing. 



Lea Brothers & Co., Philadelphia and New York. 19 



MAISCH (JOHN M.). A MANUAL OF ORGANIC MATERIA 
MEDICA. New (7th) edition, thoroughly revised by II. C. C. Maisch, 
Ph. G., Ph. D. In one very handsome l2mo. volume of 512 pages, with 
285 engravings.' Cloth, $2.50, net. 



Used as text-book in every college 
of pharmacy in the United States 
and recommended in medical col- 
leges. — American Therapist. 

Noted on both sides of the Atlantic 
and esteemed as much in Germany as 



in America. The work has no equal. 
— Dominion Med. Monthly. 

The best handbook upon phar- 
macognosy of any published in this 
country. — Boston Med. & Sur. Jonr. 



MALSBARY (GEORGE E.). A POCKET TEXT-BOOK OF 
THEORY AND PRACTICE OF MEDICINE. In one handsome 
12mo. volume of 405 pages, with 45 illustrations. Just ready.. Cloth, 
$1.75, net; flexible red leather, $2.25, net. Lea's Series of Pocket 
Text-books, edited by Bern B. Gallaudet, M. D. See page 17. 



"Will readily commend itself to 
students and busy practitioners, 
bringing forward as it does the most 
recent advances in medicine with 
the best of that which is old. It 



deals briefly and systematically with 
each disease, as to its history, a-tiol- 
ogy, symptomatology, diagnosis, 
prognosis and treatment. — Medical 
Review of Reviews. 



MANUALS. See Student's Quiz Series, page 27, Student's Series of 
Manuals, page 27, and Series of Clinical Manuals, page 25. 

MARSH (HOWARD). DISEASES OF THE JOINTS. In one 12mo. 
volume of 468 pages, with 64 engravings and a colored plate. Cloth, $2. 
See Series of Clinical Manuals, page 25. 

MARTIN (EDWARD). A MANUAL OF SURGICAL DIAGNOSIS. 
In one 12mo. volume of about 400 pp., fully illustrated. Preparing. 

MARTIN (WALTON) AND ROCKWELL (WM. H). A POCKET 
TEXT-BOOK OF CHEMISTRY AND PHYSICS. In one hand- 
some 12mo. volume of 366 pages, with 137 illustrations. Just ready. 
Cloth, $1.50, net; limp leather, $2.00, net. Lea's Series of Rocket 
Text-Books, edited by Bern B. Gallaudet, M. D. See page 17. 

rately reflects both sciences in their 
present development. The arrange- 
ment of the matter is excellent. — 
The Medical and Surgical monitor. 



Contains everything of the sci- 
ences of chemistry and physics 
necessary for the medical student 
and practitioner. The work accu- 



MAY (O. H). MANUAL OF THE DISEASES OF WOMEN. For 
the use of Students and Practitioners. Second edition, revised by L. 
S. Rau, M. D. In one 12mo. volume of 360 pages, with 31 engrav- 
ings. Cloth, $1.75. 

MEDICAL NEWS POCKET FORMULARY, see page 32. 



20 Lea Brothers & Co., Philadelphia and New York. 

MITCHELL. (S. WETR). CLINICAL LESSONS ON NEKVOUS 

DISEASES. In one 12mo. volume of 299 pages, with 19 engravings 
and 2 colored plates. Cloth, $2.50. 



contractions, rotary movements in 
the feeble minded, etc. Few can 
speak with more authority than the 
author. — The Journal of the Ameri- 
can Medical Association. 



The book treats of hysteria, recur- 
rent melancholia, disorders of sleep, 
choreic movements, false sensations 
of cold, ataxia, hemiplegic pain, 
treatment of sciatica, erythromelal- 
gia, reflex ocularneurosis, hysteric 

MITCHELL (JOHN K.). REMOTE CONSEQUENCES OF IN- 
JURIES OF NERVES AND THEIR TREATMENT. In one 

handsome 12mo. volume of 239 pages, with 12 illustrations. Cloth, $1.75. 



MORRIS (MALCOLM). DISEASES OF THE SKIN. New (2d) 
edition. In one 12mo. volume of 601 pages, with 10 chromo-litho- 
graphic plates and 26 engravings. Cloth, $3.25, net. 



The work is essentially clinical 
and practical in its scope and is 
characterized throughout by clear- 
ness and simplicity of style and 



strong common sense. It is alike 
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MULLER (J.). PRINCIPLES OF PHYSICS AND METEOROL- 
OGY. In one large 8vo. vol. of 623 pages, with 538 cuts. Cloth, $4.50. 



MUSSER (JOHN H.). A PRACTICAL TREATISE ON MEDICAL 
DIAGNOSIS, for Students and Physicians. New (3d) edition, thor- 
oughly revised. In one octavo volume of 1082 pages, with 253 en- 
gravings and 48 full-page colored plates. Cloth, $6.00, net; leather, 
$7.00, net; half Morocco, $7.50, net. 



We have no work of equal value 
in English. — University Medical 
Magazine. 

From its pages may be made the 
diagnosis of every malady that 
afflicts the human body, including 
those which in general are dealt 
with only by the specialist. — North- 
western Lancet. 



It so thoroughly meets the precise 
demands incident to modern research 
that it has been adopted as the lead- 
ing text-book by the medical colleges 
of this country. — North American 
Practitioner. 

The best of its kind, invaluable to 
the student, general practitioner and 
teacher. — Montreal Medical Journal. 



NATIONAL DISPENSATORY. See StUle, Maisch & Caspari, p. 27. 

NATIONAL FORMULARY. See Stille, Maisch & Caspari' s National 
Dispensatory, page 27. 



NATIONAL MEDICAL DICTIONARY. See Billings, page 4. 



Lea Beothebs & Co., Philadelphia and New York. 21 



NETTJjESHXP (E.). DISEASES OF THE EYE. New (Oth) American 
from sixth English edition, thoroughly revised. In one 12mo. volume 
of 502 pages, with 192 engravings, and 5 colored plates, test-types, 
formulae and color-blindness test. Cloth, $2.25, net. Just ready. 

By far the best student's text-book I The present edition is the result 
on the subject^of ophthalmology.— of revision both in England and 



The Clinical Review. 

This work for compactness, practi- 
cality and clearness has no superior 
in the English language. — Journal 
of Medicine and Science. 



America, and therefore contains the 
latest and best ophthalmological 
ideas of both continents. — The Phy- 
sician and Surgeon. 



NICHOLS (JOHN B.) AND VALE (F. P.). A POCKET TEXT- 
BOOK OF HISTOLOGY AND PATHOLOGY. In one handsome 
12mo. volume of 452 pages, with 213 illustrations. Just ready. Cloth, 
$1.75, net: flexible red leather, $2.25, net. 

Lea's Series of Pocket Text-books, edited by Been B. Gallaudet, 
M. D. See page 17. 

So systematically arranged that it can safely and conscientiously rec- 

is, in the highest degree, interesting, ommend it to both students and 

Thoroughly up to date. The book practitioners. — The St. Jouis Medi- 

is an exceptionally good one. We cal a)id Surgical Journal. 

NOKRIS (WM. F.) AND OLT^ER (CHAS. A.). TEXT-BOOK OF 

OPHTHALMOLOGY. In one octavo volume of 041 pages, with 357 
engravings and 5 colored plates. Cloth, $5 ; leather, $0. 



has ever been offered to the Amer- 
ican medical public. — Annals of 
Ophthalmology and Otology. 



It is practical in its teachings. 
We unreservedly endorse it as the 
best, the safest and the most compre- 
hensive volume upon the subject that 

OWEN (EDMUND). SURGICAL DISEASES OF CHILDREN. 

In one 12mo. volume of 525 pages, with 85 engravings and 4 colored 
plates. Cloth, $2. See Series of Clinical Manuals, page 25. 

PARK (ROSWELL). A TREATISE ON SURGERY BY AMERI- 
CAN AUTHORS. New and condensed edition. In one royal octavo 
volume of 1201 pages, with 025 engravings and 37 full-page plates. 
Cloth, $0.00, net; leather, $7.00, net. 

^^■This work is also published in a larger edition, comprising two 
volumes. Volume L, General Surgery , 799 pages, with 350 engravings 
and 21 full-page plates, in colors and monochrome. Volume II., 
Special Surgery, 800 pages, with 430 engravings and 17 full-page 
plates, in colors and monochrome. Per set, cloth, $9.00 ; leather, 
$11.00, net; half Morocco, $12.00, net. 



The work is fresh, clear and practi- 
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yet briefly, and well arranged for 
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special value to the student and busy 
practitioner. The pathology is 
broad, clear and scientific, while the 
suggestions upon treatment are 



i clear-cut, thoroughly modern and 
admirably resourceful. — Johns Hop- 
kins Hospital Bulletin. 

The latest and best work written 
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Columbus Medical Journal. 

It is thoroughly practical and yet 
thoroughly scientific. — Med. News. 



22 Lea Beothees & Co., Philadelphia and New York. 

PARK (WILLIAM H.). BACTERIOLOGY IN MEDICINE AND 

SURGERY. 12mo., 688 pages, with 87 illustrations in black and 
colors, and 2 plates. Cloth, $3.00 net. 



This book fills a very distinct 
gap. None of the text-books in our 
language take up the subject of bac- 
teriology so thoroughly and so 
soundly as does this from the point 



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health officer. The work is correct 
and very well up to date. — The Mon- 
treal Medical Journal. 



PARRY (JOHN S.). EXTRA-UTERINE PREGNANCY, ITS 
CLINICAL HISTORY, DIAGNOSIS, PROGNOSIS AND TREAT- 
MENT. In one octavo volume of 272 pages. Cloth, $2.50. 



PARVIN (THEOPHIL.US). THE SCIENCE AND ART OF OB- 
STETRICS. Third edition. In one handsome octavo volume of 
677 pages, with 267 engravings and 2 colored plates. Cloth, $4.25 ; 
leather, $5.25. 



Parvin's work is practical, con- 
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English language. — Medical Fort- 
nightly. 



PEPPER'S SYSTEM OF MEDICINE. See page 3. 

PEPPER (A. J.). FORENSIC MEDICINE. In press. See Student's 

Series of Manuals, page 27. 

SURGICAL PATHOLOGY. In one 12mo. volume of 511 pages, 



with 81 engravings. Cloth, $2. See Student's Series of Manuals, p. 27. 

PICK (T. PICKERING). FRACTURES AND DISLOCATIONS. 

In one 12mo. volume of 530 pages, with 93 engravings. Cloth, $2. 
See Series of Clinical Manuals, page 25. 

PL.AYFAIR (W. S.). A TREATISE ON THE SCIENCE AND 
PRACTICE OF MIDWIFERY. Seventh American from the ninth 
English edition. In one octavo volume of 700 pages, with 207 
engravings and 7 plates. Cloth, $3.75 net; leather, $4.75, net. 

An epitome of the science and 



practice of midwifery, which em- 
bodies all recent advances. — The 
Medical Fortnightly. 

This work must occupy a fore- 
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a safe guide to both student and 
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ties on the obstetric art. — Buffalo 
Medical and Surgical Journal. 



— THE SYSTEMATIC TREATMENT OF NERVE PROSTRA- 
TION AND HYSTERIA. In one 12mo. volume of 97 pages 
Cloth, $1. 



Lea Brothers & Co., Philadelphia and New York. 23 



POCKET FORMULARY, see page 32. 

POCKET TEXT-BOOKS, see page 18. 

POLITZER (ADAM). A TEXT-BOOK OF THE DISEASES OF THE 
EAR AND ADJACENT ORGANS. Second American from the 
third German edition. Translated by Oscar Dodd, M. D., and 
edited by Sir William Dalby, F. R. C. S. Jn one octavo volume of 
748 pages, with 330 original engravings. 

POTTS (CHARLES S.j. A POCKET TEXT-BOOK OF NERVOUS 
AND MENTAL DISEASES. In one handsome 12mo. volume of 
445 pages, with 8S engravings. Just ready. Cloth, $1.75, net; limp 
leather, $2.25, net. Lea's Series of Pocket Text-books, edited by 
Bern B. Gallaudet, M. D. See page 17. 

Dr. Potts has succeeded in de- 1 of the numerous discoveries in every 

picting the main facts in a manner branch of neurology is clearly pre- 
that will be appreciated by students sented. The book is a reliable guide. 
and general practitioners. The gist J — The Medical Bulletin. 

PROGRESSIVE MEDICINE, see page 32. 

PURDY (CHARLES TV.). BRIGHT'S DISEASE AND ALLIED 
AFFECTIONS OF THE KIDNEY. In one octavo volume of 288 
pages, with 18 engravings. Cloth, $2. 

PYE-SMITH (PHILIP H.). DISEASES OF THE SKIN. In one 

12mo. vol. of 407 pp., with 28 illus., 18 of which are colored. Cloth, $2. 

QUIZ SERIES. See Student's Quiz Series, page 27. 

RALFE (CHARLES H.). CLINICAL CHEMISTRY. In one 

12mo. volume of 314 pages, with 16 engravings. Cloth, $1.50. See 
Student's Series of Manuals, page 27. 

RAMSBOTHAM (FRANCIS H.). THE PRINCIPLES AND PRAC- 
TICE OF OBSTETRIC MEDICINE AND SURGERY. In one 
imperial octavo volume of 640 pages, with 64 plates and numerous 
engravings in the text. Strongly bound in leather, $7. 

REMSEN (IRA). THE PRINCIPLES OF THEORETICAL CHEM- 
ISTRY. New (5th) edition, thoroughly revised. In one 12mo. vol- 
ume of 326 pages. Cloth, $2. 



A clear and concise explanation 
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The book is equally adapted to the 



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— New Orleans Med. and Surg. Jour. 



24 Lea Brothers & Co., Philadelphia and New York. 

RICHARDSON (BENJAMIN WARD). PREVENTIVE MEDI- 
CINE. In one octavo volume of 729 pages. Cloth, $4 ; leather, $5. 

ROBERTS (JOHN B.). THE PRINCIPLES AND PRACTICE OF 
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838 pages with 473 engravings and 8 plates. Just ready. Cloth, $4.25, 
net ; leather, $5.25, net. 



A clear, concise, comprehensive 
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satisfactory or valuable single vol- 
ume work on this subject. — Pacific 
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ROBERTS (SIR WILXJAM). A PRACTICAL TREATISE ON 
URINARY AND RENAL DISEASES, INCLUDING URINARY 
DEPOSITS. Fourth American from the fourth London edition. In 
one very handsome 8vo. vol. of 609 pp., with 81 illus. Cloth, $3.50. 

ROSS (JAMES). A HANDBOOK OF THE DISEASES OF THE 
NERVOUS SYSTEM. In one handsome octavo volume of 726 pages, 
with 184 engravings. Cloth, $4.50 ; leather, $5.50. 

SOHAFER (EDWARD A.). THE ESSENTIALS OF HISTOL- 
OGY, DESCRIPTIVE AND PRACTICAL. For the use of Students. 
New (5th) edition. In one handsome octavo volume of 359 pages, 
with 392 illustrations. Cloth, $3.00, net. 



Nowhere else will the same very 
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structural anatomy. — The American 
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The most satisfactory elementary 
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lish language. — The Boston Med. and 
Sur. Jour. 



— A COURSE OF PRACTICAL HISTOLOGY. New (2d) edition. 
In one 12mo. volume of 307 pages, with 59 engravings. Cloth, $2.25. 



SCHLEIF (WILLIAM). MATERIA MEDIC A, THERAPEUTICS, 
PRESCRIPTION WRITING, MEDICAL LATIN, ETC. 12mo., 
352 pages. Cloth, $1.50, net; flexible red leather, $2.00, net. Just 
ready. Lea's Series of Pocket Text-books. Edited by Bern B. 
Gallatjdet, M. D. See page 17. 

We commend the book for it con- college courses on Materia Medica 

tains in a concise, definite, and as- and Therapeutics. — The National 

similable form the essential knowl- Medical Review. 
edge required in the most complete 



Lea Brothers & Co., Philadelphia and New Yoek. 26 

SCHMITZ AND ZUMPT'S CLASSICAL. SERIES. Advanced 
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cises. Cloth, 50 cents. Sallust. Cloth, 60 cents. Nepos. Cloth, 60 
cents. Virgil. Cloth, 85 cents. Curtius. Cloth, 80 cents. 

SCHOFLELD (ALFRED T.). ELEMENTARY PHYSIOLOGY 
FOR STUDENTS. In one 12mo. volume of 380 pages, with 227 
engravings and 2 colored plates. Cloth, $2. 

SENN (NICHOLAS). SURGICAL BACTERIOLOGY. Second edi- 
tion. In one octavo volume of 268 pages, with 13 plates, 10 of which 
are colored, and 9 engravings. Cloth, $2. 

SERIES OF CLINICAL MANUALS. A Series of Authoritative 
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550 pages, well illustrated. The following volumes are now ready : 
Yeo on Food in Health and Disease, new (2d) edition, $2.50; Carter 
and Frost's Ophthalmic Surgery, $2.25 ; Marsh on Diseases of the 
Joints, $2 ; Owen on Surgical Diseases of Children, $2 ; Pick on 
Fractures and Dislocations, $2 ; Savage on Insanity and Allied Neu- 
roses, $2. 
For separate notices, see under various authors' names. 

SERIES OF STUDENT'S MANUALS. See page 27. 

SIMON (CHARLES E.). CLINICAL DIAGNOSIS, BY MICRO- 
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and 18 full-page colored plates. Cloth, $3.50, net. Just ready. 

This book thoroughly deserves its I In all respects entirely up to date, 
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tic and useful manual of the micro 
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Very excellent colored plates illus- 
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The chapter on examination of 
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SIMON (W.). MANUAL OF CHEMISTRY. A Guide to Lectures 
and Laboratory Work for Beginners in Chemistry. A Text-book 
specially adapted for Students of Pharmacy and Medicine. New (6th) 
edition. In one 8vo. volume of 536 pages, with 46 engravings and 8 
plates showing colors of 64 tests. Cloth, $3.00, net. 
It is difficult to see how a better the covers of thisbook. — The North- 

book could be constructed. No man western Lancet. 

who devotes himself to the practice Its statements are all clear and its 

of medicine need know more about teachings are practical. — Virginia 

chemistry than is contained between , Med. Monthly. 



26 Lea Bkothers & Co.. Philadelphia and New York. 



SLiADE (D. D.). DIPHTHERIA; ITS NATUEE AND TREAT- 
MENT. Second edition. In one royal 12mo. vol., 158 pp. Cloth, $1.25. 



SMITH (EDWARD). 

DIABLE STAGES. 



CONSUMPTION; ITS EAKLY AND REME- 
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SMITH (J. LEWIS). A TREATISE ON THE DISEASES OF IN- 



FANCY AND CHILDHOOD 
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leather, $5.50. 
A safe guide for students and phy- 
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For years the leading text-book on 
children's diseases in America. — 
Chicago Medical Recorder. 



Eighth edition, thoroughly revised 

In one large 8vo. volume of 983 

4 full-page plates. Cloth, $4.50; 

The most complete and satisfac- 
tory text-book with which we are 
acquainted. — American Gynecologi- 
cal and Obstetrical Journal. 



SMITH (STEPHEN). OPERATIVE SURGERY. Second and thor- 
oughly revised edition. In one octavo volume of 892 pages, with 
1005 engravings. Cloth, $4 ; leather, $5. 



One of the most satisfactory works 
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dium for the modern surgeon. — Bos- 
ton Medical and Surgical Journal. 



SOLLY (S. EDWIN). A HANDBOOK OF MEDICAL CLIMA- 
TOLOGY. In one handsome octavo volume of 462 pages, with en- 
gravings and 11 full-page plates, 5 of which are in colors. Cloth, $4.00. 



Every practitioner of medicine 
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study it, and we are sure he will 
never regret it. — St. Louis Medical 
and Surgical Journal. 



A clear and lucid summary of 
what is known of climate in relation 
to its influence upon human beings. 
— The Therapeutic Gazette. 



STILLE (ALFRED). CHOLERA ; ITS ORIGIN, HISTORY, CAUS- 
ATION, SYMPTOMS, LESIONS, PREVENTION AND TREAT- 
MENT. In one 12mo. volume of 163 pages, with a chart showing 
routes of previous epidemics. Cloth, $1.25. 



— THERAPEUTICS AND MATERIA MEDICA. Fourth and 
revised edition. In two octavo volumes, containing 1936 pages. 
Cloth, $10 ; leather, $12. 



STLLLE (ALFRED), MAISCH (JOHN M.) AND CASPARI 
(CHAS. JR.). THE NATIONAL DISPENSATORY: Containing 
the Natural History, Chemistry, Pharmacy, Actions and Uses of 
Medicines, including those recognized in the latest Pharmacopoeias of 
the United States, Great Britain and Germany, with numerous refer- 
ences to the French Codex. Fifth edition, revised and enlarged, 
including the new U. S. Pharmacopoeia, Seventh Decennial Revision. 
With Supplement containing the new edition of the National Formu- 
lary. In one magnificent imperial octavo volume of about 2025 pages, 
with 320 engravings. Cloth, $7.25 ; leather, $8. With ready reference 
Thumb-letter Index. Cloth, $7.75 ; leather, $8.50. 



Lea Brothers & Co., Philadelphia and New York. 27 



STKMSON (LEWIS A.). A MANUAL OF OPERATIVE SURGERY. 

New (4th) edition. In one royal 12rno. volume of 5S1 pages, with 2!)3 
engravings. Cloth, $3.00, net. Just ready. 



A useful and practical guide for 
all students and practitioners. — Am. 
Journal of the Medical Sciences. 



The book is worth the price for the 
illustrations alone. — Ohio Medical 
Journal. 



STIMSON (LEWIS A.). A TREATISE ON FRACTURES AND 
DISLOCATIONS. In one handsome octavo volume of 831 pages, 
with 326 engravings and 20 plates. Cloth, $5.00, net; leather, 
$6.00, net; half Morocco, $6.50, net. 
Preeminently the authoritative i pensable to the student and the prac- 



text-book upon the subject. The 
vast experience of the author gives 
to his conclusions an unimpeachable 
value. The work is profusely il- 
lustrated. It will be found indis- 



titioner alike. — The Medical Age. 

The work is the best one in Eng- 
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TAYLOR (ALFRED S.). MEDICAL JURISPRUDENCE. New 

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TAYLOR (SEYMOUR). INDEX OF MEDICINE. A Manual for 
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TODD (ROBERT BENTLEY). CLINICAL LECTURES ON CER- 
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popular, and we take great pleasure 
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TREVES (FREDERICK). OPERATIVE 

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— A SYSTEM OF SURGERY. In Contributions by Twenty-five 
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TUTTL.E (GEORGE M.) 

OF CHILDREN. In one 
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Gallatjbet, M. D. See p. 

It is a good work — the author hav- 
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Pocket Text-books, edited by Bern B. 

17. 

of infancy and childhood into short 
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VAUGHAN (VICTOR C.) AND NOVY (FREDERICK G.). 

PTOMAINS, LEUCOMAINS, TOXINS AND ANTITOXINS, 

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In one 12mo. volume of 603 pages. 



The present edition has been not 
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WATSON (THOMAS). LECTURES ON THE PRINCIPLES AND 
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WEST (CHARLES). LECTURES ON THE DISEASES PECULIAR 
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ON SOME DISORDERS OF THE NERVOUS SYSTEM IN 

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WHARTON (HENRY R.). MINOR SURGERY AND BANDAG- 
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502 engravings, many of which are photographic. $3.00, net. 



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Well written, conveniently ar- 
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Lea Brothers & Co., Philadelphia and New York. 31 

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WILLIAMS (DAWSON). THE MEDICAL DISEASES OF CHIL- 
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WINCKEL ON PATHOLOGY AND TREATMENT OF CHILDBED. 

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WIPPERN (A. G.) AND BALLENGER (W. L.). Shortly. A 
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We doubt whether any book on 
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YOUNG (JAMES K.). ORTHOPEDIC SURGERY. In one 8vo. 
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In studying the different chapters, 
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It is a thorough, a very compre- 
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